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Mizobuchi K, Hayashi T, Tanaka K, Kuniyoshi K, Murakami Y, Nakamura N, Torii K, Mizota A, Sakai D, Maeda A, Kominami T, Ueno S, Kusaka S, Nishiguchi KM, Ikeda Y, Kondo M, Tsunoda K, Hotta Y, Nakano T. Genetic and Clinical Features of ABCA4-Associated Retinopathy in a Japanese Nationwide Cohort. Am J Ophthalmol 2024; 264:36-43. [PMID: 38499139 DOI: 10.1016/j.ajo.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Revised: 03/01/2024] [Accepted: 03/11/2024] [Indexed: 03/20/2024]
Abstract
PURPOSE To clarify the genetic and clinical features of Japanese patients with ABCA4-associated retinopathy. DESIGN Retrospective, multicenter cohort study. METHODS Patients with retinal degeneration and biallelic ABCA4 variants were recruited from 13 different hospitals. Whole exome sequencing analysis was used for genetic testing. Comprehensive ophthalmic examinations were performed on matched patients. The primary outcome measure was identifying multimodal retinal imaging findings associated with disease progression. RESULTS This study included 63 patients: 19 with missense/missense, 23 with missense/truncation, and 21 with truncation/truncation genotypes. In total, 62 variants were identified, including 29 novel variants. Six patients had a mild phenotype characterized by foveal-sparing or preserved foveal structure, including 4 with missense/missense and 2 with missense/truncation genotypes. The p.Arg212His variant was the most frequent in patients with mild phenotypes (4/12 alleles). Clinical findings showed a disease duration-dependent worsening of the phenotypic stage. Patients with the truncation/truncation genotype exhibited rapid retinal degeneration within a few years and definite fundus autofluorescence imaging patterns, including hyper autofluorescence at the macula and few or no flecks. CONCLUSIONS Our results indicate that missense/missense or missense/truncation genotypes, including the p.Arg212His variant, are associated with a relatively mild phenotype. In contrast, the truncation/truncation genotype causes rapid and severe retinal degeneration in Japanese patients with ABCA4-associated retinopathy. These data are vital in predicting patient prognosis, guiding genetic counseling, and stratifying patients for future clinical trials.
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Affiliation(s)
- Kei Mizobuchi
- Department of Ophthalmology (K.M., T.H., T.N.), The Jikei University School of Medicine, Tokyo, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology (K.M., T.H., T.N.), The Jikei University School of Medicine, Tokyo, Japan; Department of Ophthalmology, Katsushika Medical Center (T.H.), The Jikei University School of Medicine, Tokyo, Japan.
| | - Koji Tanaka
- Division of Ophthalmology, Department of Visual Sciences (K.T.), Nihon University School of Medicine, Nihon University Hospital, Tokyo, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology (K.K., S.K.), Kindai University Faculty of Medicine, Osaka-sayama, Japan
| | - Yusuke Murakami
- Department of Ophthalmology (Y.M.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Natsuko Nakamura
- Department of Ophthalmology (N.N.), The University of Tokyo, Tokyo, Japan
| | - Kaoruko Torii
- Department of Ophthalmology (K.T., Y.H.), Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Atsushi Mizota
- Department of Ophthalmology (A.M.), Teikyo University, Tokyo, Japan
| | - Daiki Sakai
- Department of Ophthalmology (D.S., A.M.), Kobe City Eye Hospital, Kobe, Japan
| | - Akiko Maeda
- Department of Ophthalmology (D.S., A.M.), Kobe City Eye Hospital, Kobe, Japan
| | - Taro Kominami
- Department of Ophthalmology (T.K., S.U., K.M.N.), Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Shinji Ueno
- Department of Ophthalmology (T.K., S.U., K.M.N.), Nagoya University Graduate School of Medicine, Aichi, Japan; Department of Ophthalmology (S.U.), Hirosaki University Graduate School of Medicine, Aomori, Japan
| | - Shunji Kusaka
- Department of Ophthalmology (K.K., S.K.), Kindai University Faculty of Medicine, Osaka-sayama, Japan
| | - Koji M Nishiguchi
- Department of Ophthalmology (T.K., S.U., K.M.N.), Nagoya University Graduate School of Medicine, Aichi, Japan
| | - Yasuhiro Ikeda
- Department of Ophthalmology (Y.I.), Faculty of Medicine, University of Miyazaki, Miyazaki, Japan
| | - Mineo Kondo
- Department of Ophthalmology (M.K.), Mie University Graduate School of Medicine, Mie, Japan
| | - Kazushige Tsunoda
- Division of Vision Research (K.T.), National Institute of Sensory Organs, NHO Tokyo Medical Center, Tokyo, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology (K.T., Y.H.), Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Tadashi Nakano
- Department of Ophthalmology (K.M., T.H., T.N.), The Jikei University School of Medicine, Tokyo, Japan
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Ibrahim M, Jaffal L, Assi A, Helou C, El Shamieh S. ABCA4-related retinopathies in Lebanon. Heliyon 2024; 10:e30304. [PMID: 38694055 PMCID: PMC11061736 DOI: 10.1016/j.heliyon.2024.e30304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/03/2024] Open
Abstract
Variants in ATP-binding cassette transporter type A4 (ABCA4) have been linked to several forms of inherited retinal diseases (IRDs) besides the classically defined Stargardt disease (STGD), known collectively as ABCA4 retinopathies. ABCA4 is a sizable locus harboring 50 exons; thus, its analysis has revealed over 2,400 variants described, of which more than 2,000 are causal. Due to the clinical and genetic heterogeneity, diagnosing ABCA4 retinopathies is challenging. To date, no ABCA4-related retinopathy has been detected in Lebanon. Using next-generation sequencing, we analyzed our IRDs' cohort retrospectively (61 families) and identified five with ABCA4-related retinopathies, making it a relatively abundant cause of IRDs (about 8 %). Three families were diagnosed with rod-cone dystrophy (RCD), two with STGD, and one with cone-rod dystrophy (CRD). In conclusion, our study showed the presence of ABCA4 variants with a high degree of heterogeneity in Lebanon.
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Affiliation(s)
- Mariam Ibrahim
- Molecular Testing Laboratory, Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
- Rammal Hassan Rammal Research Laboratory, PhyToxE Research Group, Faculty of Sciences, Lebanese University, Nabatieh, Lebanon
| | - Lama Jaffal
- Department of Biological and Chemical Sciences, School of Arts and Sciences, Lebanese International University, Beirut, Lebanon
| | | | - Charles Helou
- Retinal Service, Beirut Eye & ENT Specialist Hospital, Beirut, Lebanon
| | - Said El Shamieh
- Molecular Testing Laboratory, Department of Medical Laboratory Technology, Faculty of Health Sciences, Beirut Arab University, Beirut, Lebanon
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Tian L, Chen CJ, Song YN, Xu K, Li NE, Zhang XH, Xie Y, Jin ZB, Li Y. Comprehensive genetic analysis reveals the mutational landscape of ABCA4-associated retinal dystrophy in a Chinese cohort. Gene 2024; 891:147832. [PMID: 37774808 DOI: 10.1016/j.gene.2023.147832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 09/15/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
PURPOSE To depict the variant profiles of the ABCA4 gene in a large Chinese cohort of patients with ABCA4-associated retinal dystrophy (ABCA4-RD). METHODS We recruited 290 unrelated Chinese patients with ABCA4-RD and did ABCA4 mutational screening by a combination of Sanger sequencing, targeted exome sequencing, entire ABCA4 locus sequencing, and whole genome sequencing (WGS). The pathogenicity of variants was assessed using in silico tools or in vitro splicing assays following the American College of Medical Genetics and Genomics guidelines. RESULTS Two hundred sixty-eight distinct pathogenic variants were identified, and 57 were novel. In 580 alleles, 22 noncoding region variants outside canonical splice sites and 4 structural variations were found in 44 alleles accounting for 7.6% of all alleles. Bioinformatics analysis showed the complex mechanism of aberrant splicing productsnatural splice site disruption, branch point destruction, and cryptic splice site activation. Correspondingly, minigene assays validated the various abnormal splicing products, including exon skipping, exon elongation, partial exon deletion, and pseudoexon insertion. WGS identified the first inversion variation in ABCA4. CONCLUSIONS This study systematically depicted the variant profiles of ABCA4 and revealed the missing alleles of patients with ABCA4-RD in a large Chinese cohort. Our findings demonstrated the complexity of molecular diagnosis of Mendelian diseases and the efficiency of WGS for detecting structural variants.
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Affiliation(s)
- Lu Tian
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China; Department of Ophthalmology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Chun-Jie Chen
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Yu-Ning Song
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Ke Xu
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Ni-En Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Xiao-Hui Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Yue Xie
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Zi-Bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China
| | - Yang Li
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, China.
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4
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Li CHZ, Pas JAAH, Corradi Z, Hitti-Malin RJ, Hoogstede A, Runhart EH, Dhooge PPA, Collin RWJ, Cremers FPM, Hoyng CB. Study of Late-Onset Stargardt Type 1 Disease: Characteristics, Genetics, and Progression. Ophthalmology 2024; 131:87-97. [PMID: 37598860 DOI: 10.1016/j.ophtha.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/07/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023] Open
Abstract
PURPOSE Late-onset Stargardt disease is a subtype of Stargardt disease type 1 (STGD1), defined by an age of onset of 45 years or older. We describe the disease characteristics, underlying genetics, and disease progression of late-onset STGD1 and highlight the differences from geographic atrophy. DESIGN Retrospective cohort study. PARTICIPANTS Seventy-one patients with late-onset STGD1. METHODS Medical files were reviewed for clinical data including age at onset, initial symptoms, and best-corrected visual acuity. A quantitative and qualitative assessment of retinal pigment epithelium (RPE) atrophy was performed on fundus autofluorescence images and OCT scans. MAIN OUTCOME MEASURES Age at onset, genotype, visual acuity, atrophy growth rates, and loss of external limiting membrane, ellipsoid zone, and RPE. RESULTS Median age at onset was 55.0 years (range, 45-82 years). A combination of a mild and severe variant in ATP-binding cassette subfamily A member 4 (ABCA4) was the most common genotype (n = 49 [69.0%]). The most frequent allele, c.5603A→T (p.Asn1868Ile), was present in 43 of 71 patients (60.6%). No combination of 2 severe variants was found. At first presentation, all patients have flecks. Foveal-sparing atrophy was present in 33.3% of eyes, whereas 21.1% had atrophy with foveal involvement. Extrafoveal atrophy was present in 38.9% of eyes, and no atrophy was evident in 6.7% of eyes. Time-to-event curves showed a median duration of 15.4 years (95% confidence interval, 11.1-19.6 years) from onset to foveal involvement. The median visual acuity decline was -0.03 Snellen decimal per year (interquartile range [IQR], -0.07 to 0.00 Snellen decimal; 0.03 logarithm of the minimum angle of resolution). Median atrophy growth was 0.590 mm2/year (IQR, 0.046-1.641 mm2/year) for definitely decreased autofluorescence and 0.650 mm2/year (IQR, 0.299-1.729 mm2/year) for total decreased autofluorescence. CONCLUSIONS Late-onset STGD1 is a subtype of STGD1 with most commonly 1 severe and 1 mild ABCA4 variant. The general patient presents with typical fundus flecks and retinal atrophy in a foveal-sparing pattern with preserved central vision. Misdiagnosis as age-related macular degeneration should be avoided to prevent futile invasive treatments with potential complications. In addition, correct diagnosis lends patients with late-onset STGD1 the opportunity to participate in potentially beneficial therapeutic trials for STGD1. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Catherina H Z Li
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen A A H Pas
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Zelia Corradi
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Rebekkah J Hitti-Malin
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Anne Hoogstede
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Esmee H Runhart
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Patty P A Dhooge
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob W J Collin
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Frans P M Cremers
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Human Genetics, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands; Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
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5
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Rodríguez-Hidalgo M, de Bruijn SE, Corradi Z, Rodenburg K, Lara-López A, Valverde-Megías A, Ávila-Fernández A, Fernandez-Caballero L, Del Pozo-Valero M, Corominas J, Gilissen C, Irigoyen C, Cremers FPM, Ayuso C, Ruiz-Ederra J, Roosing S. ABCA4 c.6480-35A>G, a novel branchpoint variant associated with Stargardt disease. Front Genet 2023; 14:1234032. [PMID: 37779911 PMCID: PMC10539688 DOI: 10.3389/fgene.2023.1234032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Accepted: 08/15/2023] [Indexed: 10/03/2023] Open
Abstract
Introduction: Inherited retinal dystrophies (IRDs) can be caused by variants in more than 280 genes. The ATP-binding cassette transporter type A4 (ABCA4) gene is one of these genes and has been linked to Stargardt disease type 1 (STGD1), fundus flavimaculatus, cone-rod dystrophy (CRD), and pan-retinal CRD. Approximately 25% of the reported ABCA4 variants affect RNA splicing. In most cases, it is necessary to perform a functional assay to determine the effect of these variants. Methods: Whole genome sequencing (WGS) was performed in one Spanish proband with Stargardt disease. The putative pathogenicity of c.6480-35A>G on splicing was investigated both in silico and in vitro. The in silico approach was based on the deep-learning tool SpliceAI. For the in vitro approach we used a midigene splice assay in HEK293T cells, based on a previously established wild-type midigene (BA29) containing ABCA4 exons 46 to 48. Results: Through the analysis of WGS data, we identified two candidate variants in ABCA4 in one proband: a previously described deletion, c.699_768+342del (p.(Gln234Phefs*5)), and a novel branchpoint variant, c.6480-35A>G. Segregation analysis confirmed that the variants were in trans. For the branchpoint variant, SpliceAI predicted an acceptor gain with a high score (0.47) at position c.6480-47. A midigene splice assay in HEK293T cells revealed the inclusion of the last 47 nucleotides of intron 47 creating a premature stop codon and allowed to categorize the variant as moderately severe. Subsequent analysis revealed the presence of this variant as a second allele besides c.1958G>A p.(Arg653His) in an additional Spanish proband in a large cohort of IRD cases. Conclusion: A splice-altering effect of the branchpoint variant, confirmed by the midigene splice assay, along with the identification of this variant in a second unrelated individual affected with STGD, provides sufficient evidence to classify the variant as likely pathogenic. In addition, this research highlights the importance of studying non-coding regions and performing functional assays to provide a conclusive molecular diagnosis.
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Affiliation(s)
- María Rodríguez-Hidalgo
- Department of Neuroscience, Biodonostia Health Research Institute, Donostia-San Sebastián, Spain
- Department of Genetic, Physical Anthropology and Animal Physiology, University of the Basque Country UPV/EHU, Leioa, Spain
| | - Suzanne E. de Bruijn
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Kim Rodenburg
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | | | | | - Almudena Ávila-Fernández
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Lidia Fernandez-Caballero
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Del Pozo-Valero
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Jordi Corominas
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Cristina Irigoyen
- Department of Neuroscience, Biodonostia Health Research Institute, Donostia-San Sebastián, Spain
- Ophthalmology Service, Donostia Universy Hospital, Donostia-San Sebastián, Spain
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Carmen Ayuso
- Department of Genetics, Health Research Institute-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Javier Ruiz-Ederra
- Department of Neuroscience, Biodonostia Health Research Institute, Donostia-San Sebastián, Spain
- Department of Ophthalmology, University of the Basque Country (UPV/EHU), San Sebastián, Spain
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
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Sajovic J, Meglič A, Corradi Z, Khan M, Maver A, Vidmar MJ, Hawlina M, Cremers FPM, Fakin A. ABCA4 Variant c.5714+5G>A in Trans With Null Alleles Results in Primary RPE Damage. Invest Ophthalmol Vis Sci 2023; 64:33. [PMID: 37728905 PMCID: PMC10516765 DOI: 10.1167/iovs.64.12.33] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Accepted: 08/30/2023] [Indexed: 09/22/2023] Open
Abstract
Purpose To determine the disease pathogenesis associated with the frequent ABCA4 variant c.5714+5G>A (p.[=,Glu1863Leufs*33]). Methods Patient-derived photoreceptor precursor cells were generated to analyze the effect of c.5714+5G>A on splicing and perform a quantitative analysis of c.5714+5G>A products. Patients with c.5714+5G>A in trans with a null allele (i.e., c.5714+5G>A patients; n = 7) were compared with patients with two null alleles (i.e., double null patients; n = 11); with a special attention to the degree of RPE atrophy (area of definitely decreased autofluorescence and the degree of photoreceptor impairment (outer nuclear layer thickness and pattern electroretinography amplitude). Results RT-PCR of mRNA from patient-derived photoreceptor precursor cells showed exon 40 and exon 39/40 deletion products, as well as the normal transcript. Quantification of products showed 52.4% normal and 47.6% mutant ABCA4 mRNA. Clinically, c.5714+5G>A patients displayed significantly better structural and functional preservation of photoreceptors (thicker outer nuclear layer, presence of tubulations, higher pattern electroretinography amplitude) than double null patients with similar degrees of RPE loss, whereas double null patients exhibited signs of extensive photoreceptor ,damage even in the areas with preserved RPE. Conclusions The prototypical STGD1 sequence of events of primary RPE and secondary photoreceptor damage is congruous with c.5714+5G>A, but not the double null genotype, which implies different and genotype-dependent disease mechanisms. We hypothesize that the relative photoreceptor sparing in c.5714+5G>A patients results from the remaining function of the ABCA4 transporter originating from the normally spliced product, possibly by decreasing the direct bisretinoid toxicity on photoreceptor membranes.
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Affiliation(s)
- Jana Sajovic
- Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Andrej Meglič
- Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
- Max Planck Institute for Psycholinguistics, Nijmegen, the Netherlands
| | - Aleš Maver
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - Martina Jarc Vidmar
- Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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7
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Farnoodian M, Bose D, Barone F, Nelson LM, Boyle M, Jun B, Do K, Gordon W, Guerin MAK, Perera R, Ji JX, Cogliati T, Sharma R, Brooks BP, Bazan NG, Bharti K. Retina and RPE lipid profile changes linked with ABCA4 associated Stargardt's maculopathy. Pharmacol Ther 2023; 249:108482. [PMID: 37385300 PMCID: PMC10530239 DOI: 10.1016/j.pharmthera.2023.108482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/20/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Stargardt maculopathy, caused predominantly by mutations in the ABCA4 gene, is characterized by an accumulation of non-degradable visual pigment derivative, lipofuscin, in the retinal pigment epithelium (RPE) - resulting in RPE atrophy. RPE is a monolayer tissue located adjacent to retinal photoreceptors and regulates their health and functioning; RPE atrophy triggers photoreceptor cell death and vision loss in Stargardt patients. Previously, ABCA4 mutations in photoreceptors were thought to be the major contributor to lipid homeostasis defects in the eye. Recently, we demonstrated that ABCA4 loss of function in the RPE leads to cell-autonomous lipid homeostasis defects. Our work underscores that an incomplete understanding of lipid metabolism and lipid-mediated signaling in the retina and RPE are potential causes for lacking treatments for this disease. Here we report altered lipidomic in mouse and human Stargardt models. This work provides the basis for therapeutics that aim to restore lipid homeostasis in the retina and the RPE.
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Affiliation(s)
- Mitra Farnoodian
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Devika Bose
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Francesca Barone
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Luke Mathew Nelson
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Marisa Boyle
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Bokkyoo Jun
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Khanh Do
- Faculty of Medicine, Phenikaa University, Hanoi, Viet Nam
| | - William Gordon
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Marie-Audrey Kautzmann Guerin
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Rasangi Perera
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Jeff X Ji
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Tiziana Cogliati
- Division of Aging Biology, National Institute on Aging, National Institute of Health, Bethesda, MD, USA
| | - Ruchi Sharma
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institute of Health, Bethesda, MD, USA
| | - Nicolas G Bazan
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health New Orleans, New Orleans, USA
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, National Eye Institute, National Institute of Health, Bethesda, MD, USA.
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8
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Bianco L, Arrigo A, Antropoli A, Manitto MP, Martina E, Aragona E, Bandello F, Battaglia Parodi M. Association Between Genotype and Phenotype Severity in ABCA4-Associated Retinopathy. JAMA Ophthalmol 2023; 141:826-833. [PMID: 37498587 PMCID: PMC10375385 DOI: 10.1001/jamaophthalmol.2023.3188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/26/2023] [Indexed: 07/28/2023]
Abstract
Importance ABCA4-associated retinopathy is a common inherited retinal disease, and its phenotype spans from late-onset macular dystrophy to extensive cone-rod degeneration. Over 2000 disease-causing variants in the ABCA4 gene have been identified. Objective To investigate genotype-phenotype correlations in ABCA4-associated retinopathy. Design, Setting, and Participants This cohort study took place at a single referral center for inherited retinal diseases in Italy. Data were prospectively acquired from January 2015 to June 2022. Patients diagnosed with an inherited retinal disease related to biallelic ABCA4 variants were included for analysis. Exposure Genotype, classified into 4 groups according to the presence of the (1) p.Gly1961Glu allele, (2) a hypomorphic allele, (3) at least 1 moderate variant (moderate genotypes), or (4) 2 biallelic severe variants (severe genotypes). Main Outcomes and Measures Total decreased autofluorescence (TDAF) and definitely decreased autofluorescence (DDAF) areas, inner and outer retinal volumes, and the respective progression rate. Results A total of 71 patients (median [IQR] age, 34 [22.4-47.2] years; 40 [56%] female) were included in the study, and 54 (76%) were followed up for a median (IQR) of 3.5 (1.6-4.7) years. Compared with moderate genotypes, those with the p.Gly1961Glu allele had smaller TDAF lesions by 61% (95% CI, -78% to -33%; P < .001) and DDAF lesions by 77% (95% CI, -93% to -18%; P = .02), along with slower growth rates for both TDAF (0.05 mm/y; 95% CI, 0.01-0.07; P < .001) and DDAF (0.06 mm/y; 95% CI, 0-0.12; P = .004). Hypomorphic alleles were associated with a thicker inner (+0.19 mm3; 95% CI, +0.02 to +0.36; P = .03) and outer retinal volume (+0.16 mm3; 95% CI, +0.03 to +0.28; P = .01) compared with moderate genotypes as well as a slower TDAF growth rate (0.05 mm/y; 95% CI, 0.01-0.08; P = .007). Severe genotypes had a 7-fold larger TDAF area (95% CI, 3.4-14.7; P < .001) and 11-fold larger DDAF area (95% CI, 2.9-42.1; P < .001) compared with moderate genotypes, along with faster growth rates estimated at 0.16 mm/y for TDAF (95% CI, 0.12-0.20; P < .001) and 0.17 mm/y for DDAF (95% CI, 0.12-0.23; P < .001). Conclusions and Relevance In this study of ABCA4-associated retinopathy, a 4-tier classification of genotypes was found to capture substantial variation in disease phenotype severity. These findings could prove beneficial for the prognostication of patients and warrant consideration of genotype in the design of future clinical trials.
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Affiliation(s)
- Lorenzo Bianco
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessandro Arrigo
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Alessio Antropoli
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Maria Pia Manitto
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Elisabetta Martina
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Emanuela Aragona
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Francesco Bandello
- Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy
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9
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Kaltak M, Blanco-Garavito R, Molday LL, Dhaenens CM, Souied EE, Platenburg G, Swildens J, Molday RS, Cremers FPM. Stargardt disease-associated in-frame ABCA4 exon 17 skipping results in significant ABCA4 function. J Transl Med 2023; 21:546. [PMID: 37587475 PMCID: PMC10428568 DOI: 10.1186/s12967-023-04406-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/01/2023] [Indexed: 08/18/2023] Open
Abstract
BACKGROUND ABCA4, the gene implicated in Stargardt disease (STGD1), contains 50 exons, of which 17 contain multiples of three nucleotides. The impact of in-frame exon skipping is yet to be determined. Antisense oligonucleotides (AONs) have been investigated in Usher syndrome-associated genes to induce skipping of in-frame exons carrying severe variants and mitigate their disease-linked effect. Upon the identification of a STGD1 proband carrying a novel exon 17 canonical splice site variant, the activity of ABCA4 lacking 22 amino acids encoded by exon 17 was examined, followed by design of AONs able to induce exon 17 skipping. METHODS A STGD1 proband was compound heterozygous for the splice variant c.2653+1G>A, that was predicted to result in in-frame skipping of exon 17, and a null variant [c.735T>G, p.(Tyr245*)]. Clinical characteristics of this proband were studied using multi-modal imaging and complete ophthalmological examination. The aberrant splicing of c.2653+1G>A was investigated in vitro in HEK293T cells with wild-type and mutant midigenes. The residual activity of the mutant ABCA4 protein lacking Asp864-Gly885 encoded by exon 17 was analyzed with all-trans-retinal-activated ATPase activity assay, along with its subcellular localization. To induce exon 17 skipping, the effect of 40 AONs was examined in vitro in WT WERI-Rb-1 cells and 3D human retinal organoids. RESULTS Late onset STGD1 in the proband suggests that c.2653+1G>A does not have a fully deleterious effect. The in vitro splice assay confirmed that this variant leads to ABCA4 transcripts without exon 17. ABCA4 Asp864_Gly863del was stable and retained 58% all-trans-retinal-activated ATPase activity compared to WT ABCA4. This sequence is located in an unstructured linker region between transmembrane domain 6 and nucleotide-binding domain-1 of ABCA4. AONs were designed to possibly reduce pathogenicity of severe variants harbored in exon 17. The best AON achieved 59% of exon 17 skipping in retinal organoids. CONCLUSIONS Exon 17 deletion in ABCA4 does not result in the absence of protein activity and does not cause a severe STGD1 phenotype when in trans with a null allele. By applying AONs, the effect of severe variants in exon 17 can potentially be ameliorated by exon skipping, thus generating partial ABCA4 activity in STGD1 patients.
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Affiliation(s)
- Melita Kaltak
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- ProQR Therapeutics, Leiden, The Netherlands
| | - Rocio Blanco-Garavito
- Department of Ophthalmology, Intercommunal Hospital Center and Henri Mondor Hospital, Paris-Est Créteil University, Creteil, France
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, BC, Canada
| | - Claire-Marie Dhaenens
- University of Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
| | - Eric E Souied
- Department of Ophthalmology, Intercommunal Hospital Center and Henri Mondor Hospital, Paris-Est Créteil University, Creteil, France
| | | | | | - Robert S Molday
- Department of Biochemistry and Molecular Biology, Department of Ophthalmology and Visual Sciences, Centre for Macular Research, University of British Columbia, Vancouver, BC, Canada
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
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10
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Whelan L, Dockery A, Stephenson KAJ, Zhu J, Kopčić E, Post IJM, Khan M, Corradi Z, Wynne N, O' Byrne JJ, Duignan E, Silvestri G, Roosing S, Cremers FPM, Keegan DJ, Kenna PF, Farrar GJ. Detailed analysis of an enriched deep intronic ABCA4 variant in Irish Stargardt disease patients. Sci Rep 2023; 13:9380. [PMID: 37296172 PMCID: PMC10256698 DOI: 10.1038/s41598-023-35889-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Over 15% of probands in a large cohort of more than 1500 inherited retinal degeneration patients present with a clinical diagnosis of Stargardt disease (STGD1), a recessive form of macular dystrophy caused by biallelic variants in the ABCA4 gene. Participants were clinically examined and underwent either target capture sequencing of the exons and some pathogenic intronic regions of ABCA4, sequencing of the entire ABCA4 gene or whole genome sequencing. ABCA4 c.4539 + 2028C > T, p.[= ,Arg1514Leufs*36] is a pathogenic deep intronic variant that results in a retina-specific 345-nucleotide pseudoexon inclusion. Through analysis of the Irish STGD1 cohort, 25 individuals across 18 pedigrees harbour ABCA4 c.4539 + 2028C > T and another pathogenic variant. This includes, to the best of our knowledge, the only two homozygous patients identified to date. This provides important evidence of variant pathogenicity for this deep intronic variant, highlighting the value of homozygotes for variant interpretation. 15 other heterozygous incidents of this variant in patients have been reported globally, indicating significant enrichment in the Irish population. We provide detailed genetic and clinical characterization of these patients, illustrating that ABCA4 c.4539 + 2028C > T is a variant of mild to intermediate severity. These results have important implications for unresolved STGD1 patients globally with approximately 10% of the population in some western countries claiming Irish heritage. This study exemplifies that detection and characterization of founder variants is a diagnostic imperative.
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Affiliation(s)
- Laura Whelan
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland.
| | - Adrian Dockery
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
- Next Generation Sequencing Laboratory, Pathology Department, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Kirk A J Stephenson
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Julia Zhu
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Ella Kopčić
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Iris J M Post
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- International Max Planck Research School for Language Sciences, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Niamh Wynne
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - James J O' Byrne
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
- International Max Planck Research School for Language Sciences, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- National Centre for Inherited Metabolic Disorders, The Mater Misericordiae University Hospital, Dublin 7, Ireland
- School of Medicine, Trinity College Dublin, Dublin 2, Ireland
| | - Emma Duignan
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - Giuliana Silvestri
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, Northern Ireland, UK
- School of Medicine, University College Dublin, Dublin 4, Ireland
- Department of Ophthalmology, The Royal Victoria Hospital, Belfast, Northern Ireland, UK
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Nijmegen, and Maastricht University Medical Center+, Maastricht, The Netherlands
| | - David J Keegan
- Mater Clinical Ophthalmic Genetics Unit, The Mater Misericordiae University Hospital, Dublin 7, Ireland
| | - Paul F Kenna
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin 2, Ireland
| | - G Jane Farrar
- The School of Genetics and Microbiology, Trinity College Dublin, Dublin 2, Ireland
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11
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Cevik S, Biswas SB, Biswas-Fiss EE. Structural and Pathogenic Impacts of ABCA4 Variants in Retinal Degenerations-An In-Silico Study. Int J Mol Sci 2023; 24:ijms24087280. [PMID: 37108442 PMCID: PMC10138569 DOI: 10.3390/ijms24087280] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 04/11/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
The retina-specific ATP-binding cassette transporter protein ABCA4 is responsible for properly continuing the visual cycle by removing toxic retinoid byproducts of phototransduction. Functional impairment caused by ABCA4 sequence variations is the leading cause of autosomal recessive inherited retinal disorders, including Stargardt disease, retinitis pigmentosa, and cone-rod dystrophy. To date, more than 3000 ABCA4 genetic variants have been identified, approximately 40 percent of which have not been able to be classified for pathogenicity assessments. This study examined 30 missense ABCA4 variants using AlphaFold2 protein modeling and computational structure analysis for pathogenicity prediction. All variants classified as pathogenic (n = 10) were found to have deleterious structural consequences. Eight of the ten benign variants were structurally neutral, while the remaining two resulted in mild structural changes. This study's results provided multiple lines of computational pathogenicity evidence for eight ABCA4 variants of uncertain clinical significance. Overall, in silico analyses of ABCA4 can provide a valuable tool for understanding the molecular mechanisms of retinal degeneration and their pathogenic impact.
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Affiliation(s)
- Senem Cevik
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Subhasis B Biswas
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
| | - Esther E Biswas-Fiss
- Department of Medical and Molecular Sciences, College of Health Sciences, University of Delaware, 16 West Main Street, Suite 302 WHL, Newark, DE 19716, USA
- Ammon Pinizzotto Biopharmaceutical Innovation Center, 590 Avenue 1743, Newark, DE 19713, USA
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12
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Kaltak M, de Bruijn P, Piccolo D, Lee SE, Dulla K, Hoogenboezem T, Beumer W, Webster AR, Collin RW, Cheetham ME, Platenburg G, Swildens J. Antisense oligonucleotide therapy corrects splicing in the common Stargardt disease type 1-causing variant ABCA4 c.5461-10T>C. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 31:674-688. [PMID: 36910710 PMCID: PMC9999166 DOI: 10.1016/j.omtn.2023.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 02/15/2023] [Indexed: 02/20/2023]
Abstract
Stargardt disease type 1 (STGD1) is the most common hereditary form of maculopathy and remains untreatable. STGD1 is caused by biallelic variants in the ABCA4 gene, which encodes the ATP-binding cassette (type 4) protein (ABCA4) that clears toxic byproducts of the visual cycle. The c.5461-10T>C p.[Thr1821Aspfs∗6,Thr1821Valfs∗13] variant is the most common severe disease-associated variant, and leads to exon skipping and out-of-frame ABCA4 transcripts that prevent translation of functional ABCA4 protein. Homozygous individuals typically display early onset STGD1 and are legally blind by early adulthood. Here, we applied antisense oligonucleotides (AONs) to promote exon inclusion and restore wild-type RNA splicing of ABCA4 c.5461-10T>C. The effect of AONs was first investigated in vitro using an ABCA4 midigene model. Subsequently, the best performing AONs were administered to homozygous c.5461-10T>C 3D human retinal organoids. Isoform-specific digital polymerase chain reaction revealed a significant increase in correctly spliced transcripts after treatment with the lead AON, QR-1011, up to 53% correct transcripts at a 3 μM dose. Furthermore, western blot and immunohistochemistry analyses identified restoration of ABCA4 protein after treatment. Collectively, we identified QR-1011 as a potent splice-correcting AON and a possible therapeutic intervention for patients harboring the severe ABCA4 c.5461-10T>C variant.
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Affiliation(s)
- Melita Kaltak
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
- Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 GA Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 GA Nijmegen, and Maastricht University Medical Center+, P. Debyelaan 25, 6229 HX Maastricht, the Netherlands
| | - Petra de Bruijn
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
| | - Davide Piccolo
- UCL, Institute of Ophthalmology, 11-43 Bath Street, EC1V 9EL London, UK
| | - Sang-Eun Lee
- UCL, Institute of Ophthalmology, 11-43 Bath Street, EC1V 9EL London, UK
| | - Kalyan Dulla
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
| | | | - Wouter Beumer
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
| | - Andrew R. Webster
- UCL, Institute of Ophthalmology, 11-43 Bath Street, EC1V 9EL London, UK
- Moorfields Eye Hospital, 162 City Road, EC1V 2PD London, UK
| | - Rob W.J. Collin
- Department of Human Genetics, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 GA Nijmegen, the Netherlands
- Academic Alliance Genetics, Radboud University Medical Center, Geert Grooteplein-Zuid 10, 6525 GA Nijmegen, and Maastricht University Medical Center+, P. Debyelaan 25, 6229 HX Maastricht, the Netherlands
| | | | | | - Jim Swildens
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
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13
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Tomkiewicz TZ, Nieuwenhuis SE, Cremers FPM, Garanto A, Collin RWJ. Correction of the Splicing Defect Caused by a Recurrent Variant in ABCA4 (c.769-784C>T) That Underlies Stargardt Disease. Cells 2022; 11:3947. [PMID: 36552712 PMCID: PMC9777113 DOI: 10.3390/cells11243947] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/23/2022] [Accepted: 11/26/2022] [Indexed: 12/13/2022] Open
Abstract
Stargardt disease is an inherited retinal disease caused by biallelic mutations in the ABCA4 gene, many of which affect ABCA4 splicing. In this study, nine antisense oligonucleotides (AONs) were designed to correct pseudoexon (PE) inclusion caused by a recurrent deep-intronic variant in ABCA4 (c.769-784C>T). First, the ability of AONs to skip the PE from the final ABCA4 mRNA transcript was assessed in two cellular models carrying the c.769-784C>T variant: a midigene assay using HEK293T cells and patient-derived fibroblasts. Based on the splicing-correcting ability of each individual AON, the three most efficacious AONs targeting independent regions of the PE were selected for a final assessment in photoreceptor precursor cells (PPCs). The final analysis in the PPC model confirmed high efficacy of AON2, -5, and -7 in promoting PE exclusion. Among the three AONs, AON2 is chosen as the lead candidate for further optimization, hereby showcasing the high potential of AONs to correct aberrant splicing events driven by deep-intronic variants.
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Affiliation(s)
- Tomasz Z. Tomkiewicz
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Sara E. Nieuwenhuis
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Alejandro Garanto
- Departments of Pediatrics, Amalia Children’s Hospital, Human Genetics and Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
| | - Rob W. J. Collin
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 GA Nijmegen, The Netherlands
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14
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Huang D, Thompson JA, Chen SC, Adams A, Pitout I, Lima A, Zhang D, Jeffery RCH, Attia MS, McLaren TL, Lamey TM, De Roach JN, McLenachan S, Aung-Htut MT, Fletcher S, Wilton SD, Chen FK. Characterising splicing defects of ABCA4 variants within exons 13-50 in patient-derived fibroblasts. Exp Eye Res 2022; 225:109276. [PMID: 36209838 DOI: 10.1016/j.exer.2022.109276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 09/12/2022] [Accepted: 09/28/2022] [Indexed: 12/29/2022]
Abstract
The ATP-binding cassette subfamily A member 4 gene (ABCA4)-associated retinopathy, Stargardt disease, is the most common monogenic inherited retinal disease. Given the pathogenicity of numerous ABCA4 variants is yet to be examined and a significant proportion (more than 15%) of ABCA4 variants are categorized as splice variants in silico, we therefore established a fibroblast-based splice assay to analyze ABCA4 variants in an Australian Stargardt disease cohort and characterize the pathogenic mechanisms of ABCA4 variants. A cohort of 67 patients clinically diagnosed with Stargardt disease was recruited. Genomic DNA was analysed using a commercial panel for ABCA4 variant detection and the consequences of ABCA4 variants were predicted in silico. Dermal fibroblasts were propagated from skin biopsies, total RNA was extracted and the ABCA4 transcript was amplified by RT-PCR. Our analysis identified a total of 67 unique alleles carrying 74 unique variants. The most prevalent splice-affecting complex allele c.[5461-10T>C; 5603A>T] was carried by 10% of patients in a compound heterozygous state. ABCA4 transcripts from exon 13 to exon 50 were readily detected in fibroblasts. In this region, aberrant splicing was evident in 10 out of 57 variant transcripts (18%), carried by 19 patients (28%). Patient-derived fibroblasts provide a feasible platform for identification of ABCA4 splice variants located within exons 13-50. Experimental evidence of aberrant splicing contributes to the pathogenic classification for ABCA4 variants. Moreover, identification of variants that affect splicing processes provides opportunities for intervention, in particular antisense oligonucleotide-mediated splice correction.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Abbie Adams
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Ianthe Pitout
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Alanis Lima
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, East Melbourne, Victoria, Australia
| | - Mary S Attia
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Tina M Lamey
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - John N De Roach
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia; PYC Therapeutics, Harry Perkins Institute of Medical Research, Verdun St, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Fred K Chen
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Victoria, Australia; Royal Victorian Eye and Ear Hospital, Centre for Eye Research Australia, East Melbourne, Victoria, Australia.
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15
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Hou W, Xu D, Wang L, Chen Y, Chen Z, Zhou C, Chen Y. Plastic structures for diverse substrates: A revisit of human
ABC
transporters. Proteins 2022; 90:1749-1765. [DOI: 10.1002/prot.26406] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 12/18/2022]
Affiliation(s)
- Wen‐Tao Hou
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Da Xu
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Liang Wang
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Yu Chen
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Zhi‐Peng Chen
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Cong‐Zhao Zhou
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
| | - Yuxing Chen
- School of Life Sciences University of Science and Technology of China Hefei People's Republic of China
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16
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De Angeli P, Reuter P, Hauser S, Schöls L, Stingl K, Wissinger B, Kohl S. Effective splicing restoration of a deep-intronic ABCA4 variant in cone photoreceptor precursor cells by CRISPR/SpCas9 approaches. MOLECULAR THERAPY - NUCLEIC ACIDS 2022; 29:511-524. [PMID: 35991315 PMCID: PMC9375153 DOI: 10.1016/j.omtn.2022.07.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/20/2022] [Indexed: 12/26/2022]
Affiliation(s)
- Pietro De Angeli
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, 72076 Tübingen, Germany
- Corresponding author Pietro De Angeli, Institute for Ophthalmic Research, Centre for Ophthalmology, Elfriede-Aulhorn-Strasse 5–7, 72076 Tübingen, Germany.
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, 72076 Tübingen, Germany
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, 72076 Tübingen, Germany
| | - Katarina Stingl
- Centre for Ophthalmology, University Hospital Tübingen, 72076 Tübingen, Germany
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tübingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Hospital Tübingen, 72076 Tübingen, Germany
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17
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Kazmierczak de Camargo JP, Prezia GNDB, Shiokawa N, Sato MT, Rosati R, Beate Winter Boldt A. New Insights on the Regulatory Gene Network Disturbed in Central Areolar Choroidal Dystrophy-Beyond Classical Gene Candidates. Front Genet 2022; 13:886461. [PMID: 35656327 PMCID: PMC9152281 DOI: 10.3389/fgene.2022.886461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Central areolar choroidal dystrophy (CACD) is a rare hereditary disease that mainly affects the macula, resulting in progressive and usually profound visual loss. Being part of congenital retinal dystrophies, it may have an autosomal dominant or recessive inheritance and, until now, has no effective treatment. Given the shortage of genotypic information about the disease, this work systematically reviews the literature for CACD-causing genes. Three independent researchers selected 33 articles after carefully searching and filtering the Scielo, Pubmed, Lilacs, Web of Science, Scopus, and Embase databases. Mutations of six genes (PRPH2, GUCA1A, GUCY2D, CDHR1, ABCA4, and TTLL5) are implicated in the monogenic dominant inheritance of CACD. They are functionally related to photoreceptors (either in the phototransduction process, as in the case of GUCY2D, or the recovery of retinal photodegradation in photoreceptors for GUCA1A, or the formation and maintenance of specific structures within photoreceptors for PRPH2). The identified genetic variants do not explain all observed clinical features, calling for further whole-genome and functional studies for this disease. A network analysis with the CACD-related genes identified in the systematic review resulted in the identification of another 20 genes that may influence CACD onset and symptoms. Furthermore, an enrichment analysis allowed the identification of 13 transcription factors and 4 long noncoding RNAs interacting with the products of the previously mentioned genes. If mutated or dysregulated, they may be directly involved in CACD development and related disorders. More than half of the genes identified by bioinformatic tools do not appear in commercial gene panels, calling for more studies about their role in the maintenance of the retina and phototransduction process, as well as for a timely update of these gene panels.
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Affiliation(s)
| | - Giovanna Nazaré de Barros Prezia
- Post-Graduation Program in Biotechnology Applied to Child and Adolescent Health, Faculdades Pequeno Príncipe and Pelé Pequeno Príncipe Research Institute, Curitiba, Brazil
| | - Naoye Shiokawa
- Retina and Vitreo Consulting Eye Clinic, Curitiba, Brazil
| | - Mario Teruo Sato
- Retina and Vitreo Consulting Eye Clinic, Curitiba, Brazil.,Department of Ophthalmol/Otorhinolaryngology, Federal University of Paraná, Curitiba, Brazil
| | - Roberto Rosati
- Post-Graduation Program in Biotechnology Applied to Child and Adolescent Health, Faculdades Pequeno Príncipe and Pelé Pequeno Príncipe Research Institute, Curitiba, Brazil
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18
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Vázquez-Domínguez I, Li CHZ, Fadaie Z, Haer-Wigman L, Cremers FPM, Garanto A, Hoyng CB, Roosing S. Identification of a Complex Allele in IMPG2 as a Cause of Adult-Onset Vitelliform Macular Dystrophy. Invest Ophthalmol Vis Sci 2022; 63:27. [PMID: 35608844 PMCID: PMC9150824 DOI: 10.1167/iovs.63.5.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 04/21/2022] [Indexed: 12/25/2022] Open
Abstract
Purpose Inherited retinal diseases are a group of clinically and genetically heterogeneous disorders with approximately 270 genes involved. IMPG2 is associated with adult-onset vitelliform macular dystrophy. Here, we investigated two unrelated patients with vitelliform macular dystrophy to identify the underlying genetic cause. Methods Whole-exome sequencing identified a putative causal complex allele consisting of c.3023-15T>A and c.3023G>A (p.(Gly1008Asp)) in IMPG2 in both individuals. To assess its effect, in vitro splice assays in HEK293T and further characterization in patient-derived photoreceptor precursor cells (PPCs) were conducted. Results The results of the midigene splice assays in HEK293T showed that the complex allele causes a variety of splicing defects ranging from a small deletion to (multiple-)exon skipping. This finding was further validated using patient-derived PPCs that showed a significant increase of out-of-frame transcripts lacking one or multiple exons compared to control-derived PPCs. Overall, control PPCs consistently showed low levels of aberrantly spliced IMPG2 transcripts that were highly elevated in patient-derived PPCs. These differences were even more obvious upon inhibition of nonsense-mediated decay with cycloheximide. Conclusions We report a heterozygous complex allele in IMPG2 causative for adult-onset vitelliform macular dystrophy in two unrelated individuals with mild visual loss and bilateral vitelliform lesions. The predicted causal missense mutation c.3023G>A, located in the consensus splice acceptor site, enhances the splicing effect of the upstream variant c.3023-15T>A, leading to the generation of aberrant transcripts that decrease the full-length IMPG2 levels. These results suggest a haploinsufficiency mechanism of action and highlight the complementarity of using different models to functionally assesses splicing defects.
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Affiliation(s)
- Irene Vázquez-Domínguez
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Catherina H. Z. Li
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Alejandro Garanto
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Pediatrics, Amalia Children's Hospital and Radboud Institute of Molecular Life Sciences (RIMLS), Radboud University Medical Center, Nijmegen, the Netherlands
| | - Carel B. Hoyng
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
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19
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Wang Y, Sun W, Zhou J, Li X, Jiang Y, Li S, Jia X, Xiao X, Ouyang J, Wang Y, Zhou L, Long Y, Liu M, Li Y, Yi Z, Wang P, Zhang Q. Different Phenotypes Represent Advancing Stages of ABCA4-Associated Retinopathy: A Longitudinal Study of 212 Chinese Families From a Tertiary Center. Invest Ophthalmol Vis Sci 2022; 63:28. [PMID: 35608843 PMCID: PMC9150840 DOI: 10.1167/iovs.63.5.28] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the nature and association of different phenotypes associated with ABCA4 mutations in Chinese. Methods All patients were recruited from our pediatric and genetic eye clinic. Detailed ocular phenotypes were characterized. The disease course was evaluated by long-term follow-up observation, with a focus on fundus changes. Cox regression was used to identify the factors associated with disease progression. Results A systematic review of genetic and clinical data for 228 patients and follow-up data for 42 patients indicated specific features in patients with two ABCA4 variants. Of 185 patients with available fundus images, 107 (57.8%) showed focal lesions restricted to the central macula without flecks. Among these 107 patients, 30 patients (28.0%) initially presented with relatively preserved visual acuity and inconspicuous performance on routine fundus screening. A pigmentary change in the posterior pole was observed in 22 of 185 patients (11.9%), and this change mimicked retinitis pigmentosa in 10 cases (45.5%). Follow-up visits and sibling comparisons demonstrated disease progression from cone-rod dystrophy, Stargardt disease, to retinitis pigmentosa. An earlier age of onset was associated with a more rapid decrease in visual acuity (P = 0.03). Patients with two truncation variants had an earlier age of onset. Conclusion Phenotypic variation in ABCA4-associated retinopathy may represent sequential changes in a single disease: early-stage Stargardt disease may resemble cone-rod dystrophy, whereas the presence of diffuse pigmentation in the late stage may mimic retinitis pigmentosa. Recognizing the natural progression of fundus changes, especially those visualized by wide-field fundus autofluorescence, is valuable for diagnostics and therapeutic decision-making.
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Affiliation(s)
- Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jing Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueqing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yueye Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lin Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yuxi Long
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Mengchu Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yongyu Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zhen Yi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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20
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Corradi Z, Salameh M, Khan M, Héon E, Mishra K, Hitti-Malin RJ, AlSwaiti Y, Aslanian A, Banin E, Brooks BP, Zein WM, Hufnagel RB, Roosing S, Dhaenens C, Sharon D, Cremers FPM, AlTalbishi A. ABCA4 c.859-25A>G, a Frequent Palestinian Founder Mutation Affecting the Intron 7 Branchpoint, Is Associated With Early-Onset Stargardt Disease. Invest Ophthalmol Vis Sci 2022; 63:20. [PMID: 35475888 PMCID: PMC9055564 DOI: 10.1167/iovs.63.4.20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 04/02/2022] [Indexed: 11/24/2022] Open
Abstract
Purpose The effect of noncoding variants is often unknown in the absence of functional assays. Here, we characterized an ABCA4 intron 7 variant, c.859-25A>G, identified in Palestinian probands with Stargardt disease (STGD) or cone-rod dystrophy (CRD). We investigated the effect of this variant on the ABCA4 mRNA and retinal phenotype, and its prevalence in Palestine. Methods The ABCA4 gene was sequenced completely or partially in 1998 cases with STGD or CRD. The effect of c.859-25A>G on splicing was investigated in silico using SpliceAI and in vitro using splice assays. Homozygosity mapping was performed for 16 affected individuals homozygous for c.859-25A>G. The clinical phenotype was assessed using functional and structural analyses including visual acuity, full-field electroretinography, and multimodal imaging. Results The smMIPs-based ABCA4 sequencing revealed c.859-25A>G in 10 Palestinian probands from Hebron and Jerusalem. SpliceAI predicted a significant effect of this putative branchpoint-inactivating variant on the nearby intron 7 splice acceptor site. Splice assays revealed exon 8 skipping and two partial inclusions of intron 7, each having a deleterious effect. Additional genotyping revealed another 46 affected homozygous or compound heterozygous individuals carrying variant c.859-25A>G. Homozygotes shared a genomic segment of 59.6 to 87.9 kb and showed severe retinal defects on ophthalmoscopic evaluation. Conclusions The ABCA4 variant c.859-25A>G disrupts a predicted branchpoint, resulting in protein truncation because of different splice defects, and is associated with early-onset STGD1 when present in homozygosity. This variant was found in 25/525 Palestinian inherited retinal dystrophy probands, representing one of the most frequent inherited retinal disease-causing variants in West-Bank Palestine.
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Affiliation(s)
- Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Manar Salameh
- St John of Jerusalem Eye Hospital Group, East Jerusalem, Palestine
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mubeen Khan
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Ketan Mishra
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rebekkah J. Hitti-Malin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Yahya AlSwaiti
- St John of Jerusalem Eye Hospital Group, East Jerusalem, Palestine
| | - Alice Aslanian
- St John of Jerusalem Eye Hospital Group, East Jerusalem, Palestine
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian P. Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institutes, National Institutes of Health, Bethesda, Maryland, United States
| | - Wadih M. Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institutes, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert B. Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institutes, National Institutes of Health, Bethesda, Maryland, United States
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Claire‐Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Univ. Lille, Inserm, CHU Lille, U1172 - LilNCog - Lille Neuroscience & Cognition, Lille, France
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Frans P. M. Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Alaa AlTalbishi
- St John of Jerusalem Eye Hospital Group, East Jerusalem, Palestine
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21
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Genetic characteristics of 234 Italian patients with macular and cone/cone-rod dystrophy. Sci Rep 2022; 12:3774. [PMID: 35260635 PMCID: PMC8904500 DOI: 10.1038/s41598-022-07618-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Accepted: 02/16/2022] [Indexed: 01/09/2023] Open
Abstract
Two-hundred and thirty-four Italian patients with a clinical diagnosis of macular, cone and cone-rod dystrophies (MD, CD, and CRD) were examined using next-generation sequencing (NGS) and gene sequencing panels targeting a specific set of genes, Sanger sequencing and—when necessary—multiplex ligation-dependent probe amplification (MLPA) to diagnose the molecular cause of the aforementioned diseases. When possible, segregation analysis was performed in order to confirm unsolved cases. Each patient’s retinal phenotypic characteristics were determined using focal and full-field ERGs, perimetry, spectral domain optical coherence tomography and fundus autofluorescence. We identified 236 potentially causative variants in 136 patients representing the 58.1% of the total cohort, 43 of which were unpublished. After stratifying the patients according to their clinical suspicion, the diagnostic yield was 62.5% and 53.8% for patients with MD and for those with CD/CRD, respectively. The mode of inheritance of all cases confirmed by genetic analysis was 70% autosomal recessive, 26% dominant, and 4% X-linked. The main cause (59%) of both MD and CD/CRD cases was the presence of variants in the ABCA4 gene, followed by variants in PRPH2 (9%) and BEST1 (6%). A careful morpho-functional evaluation of the phenotype, together with genetic counselling, resulted in an acceptable diagnostic yield in a large cohort of Italian patients. Our study emphasizes the role of targeted NGS to diagnose MDs, CDs, and CRDs, as well as the clinical usefulness of segregation analysis for patients with unsolved diagnosis.
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22
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Cornelis SS, Runhart EH, Bauwens M, Corradi Z, De Baere E, Roosing S, Haer-Wigman L, Dhaenens CM, Vulto-van Silfhout AT, Cremers FP. Personalized genetic counseling for Stargardt disease: Offspring risk estimates based on variant severity. Am J Hum Genet 2022; 109:498-507. [PMID: 35120629 DOI: 10.1016/j.ajhg.2022.01.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 01/11/2022] [Indexed: 12/21/2022] Open
Abstract
Recurrence risk calculations in autosomal recessive diseases are complicated when the effect of genetic variants and their population frequencies and penetrances are unknown. An example of this is Stargardt disease (STGD1), a frequent recessive retinal disease caused by bi-allelic pathogenic variants in ABCA4. In this cross-sectional study, 1,619 ABCA4 variants from 5,579 individuals with STGD1 were collected and categorized by (1) severity based on statistical comparisons of their frequencies in STGD1-affected individuals versus the general population, (2) their observed versus expected homozygous occurrence in STGD1-affected individuals, (3) their occurrence in combination with established mild alleles in STGD1-affected individuals, and (4) previous functional and clinical studies. We used the sum allele frequencies of these severity categories to estimate recurrence risks for offspring of STGD1-affected individuals and carriers of pathogenic ABCA4 variants. The risk for offspring of an STGD1-affected individual with the "severe|severe" genotype or a "severe|mild with complete penetrance" genotype to develop STGD1 at some moment in life was estimated at 2.8%-3.1% (1 in 36-32 individuals) and 1.6%-1.8% (1 in 62-57 individuals), respectively. The risk to develop STGD1 in childhood was estimated to be 2- to 4-fold lower: 0.68%-0.79% (1 in 148-126) and 0.34%-0.39% (1 in 296-252), respectively. In conclusion, we established personalized recurrence risk calculations for STGD1-affected individuals with different combinations of variants. We thus propose an expanded genotype-based personalized counseling to appreciate the variable recurrence risks for STGD1-affected individuals. This represents a conceptual breakthrough because risk calculations for STGD1 may be exemplary for many other inherited diseases.
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23
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Del Pozo-Valero M, Riveiro-Alvarez R, Martin-Merida I, Blanco-Kelly F, Swafiri S, Lorda-Sanchez I, Trujillo-Tiebas MJ, Carreño E, Jimenez-Rolando B, Garcia-Sandoval B, Corton M, Avila-Fernandez A, Ayuso C. Impact of Next Generation Sequencing in Unraveling the Genetics of 1036 Spanish Families With Inherited Macular Dystrophies. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 35119454 PMCID: PMC8819279 DOI: 10.1167/iovs.63.2.11] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose To assess the potential of next-generation sequencing (NGS) technologies to characterize cases diagnosed with autosomal recessive (ar) or sporadic (s) macular dystrophies (ar/sMD) and describe their mutational spectrum. Methods A cohort of 1036 families was classified according to their suspected clinical diagnosis—Stargardt disease (STGD), cone and cone-rod dystrophy (CCRD) or other maculopathies (otherMD). Molecular studies included genotyping microarrays, Sanger sequencing, NGS, and sequencing of intronic regions of the ABCA4 gene. Clinical reclassification was done after the genetic study. Results At the end of the study, 677 patients (65%) had a confirmed genetic diagnosis, representing 78%, 63%, and 38% of STGD, CCRD, and otherMD groups of patients, respectively. ABCA4 is the most mutated gene in all groups, and a second pathogenic variant was found in 76% of STGD patients with one previously identified mutated ABCA4 allele. Autosomal dominant or X-linked mutations were found in 5% of cases together with not-MD genes (CHM, EYS, RHO, RPGR, RLBP1, OPA1, and USH2A among others) leading to their reclassification. Novel variants in the very rare genes PLA2G5 and TTLL5 revealed additional phenotypic associations. Conclusions This study provides for the first time a genetic landscape of 1036 ar/sMD families according to their suspected diagnosis. The analysis of >200 genes associated with retinal dystrophies and the entire locus of ABCA4 increase the rate of characterization, even regardless of available clinical and familiar data. The use of the suspected a priori diagnosis referred by the clinicians, especially in the past, could lead to clinical reclassifications to other inherited retinal dystrophies.
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Affiliation(s)
- Marta Del Pozo-Valero
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Rosa Riveiro-Alvarez
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Inmaculada Martin-Merida
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Saoud Swafiri
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Isabel Lorda-Sanchez
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Maria José Trujillo-Tiebas
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Ester Carreño
- Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Belen Jimenez-Rolando
- Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Blanca Garcia-Sandoval
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain.,Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - Marta Corton
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Almudena Avila-Fernandez
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
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24
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Xiao X, Ye L, Chen C, Zheng H, Yuan J. Clinical Observation and Genotype-Phenotype Analysis of ABCA4- Related Hereditary Retinal Degeneration before Gene Therapy. Curr Gene Ther 2022; 22:342-351. [PMID: 35170407 PMCID: PMC10495610 DOI: 10.2174/1566523222666220216101539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hereditary retinal degeneration (HRD) is an irreversible eye disease that results in blindness in severe cases. It is most commonly caused by variants in the ABCA4 gene. HRD presents a high degree of clinical and genetic heterogeneity. We determined genotypic and phenotypic correlations, in the natural course of clinical observation, of unrelated progenitors of HRD associated with ABCA4. OBJECTIVE To analyze the relationship between the phenotypes and genotypes of ABCA4 variants. METHODS A retrospective clinical study of five cases from the ophthalmology department of the People's Hospital of Wuhan University from January 2019 to October 2020 was conducted. We tested for ABCA4 variants in the probands. We performed eye tests, including the best-corrected visual acuity, super-wide fundus photography and spontaneous fluorescence photography, optical coherence tomography, and electrophysiological examination. RESULTS Disease-causing variants were identified in the ABCA4 genes of all patients. Among these, seven ABCA4 variants were novel. All patients were sporadic cases; only one patient had parents who were relatives, and the other four patients were offspring of unrelated parents. Two patients presented with Stargardt disease, mainly with macular lesions, two presented with retinitis pigmentosa (cone-rod type), and one presented with cone dystrophy. The visual acuity and visual field of the five patients showed varying degrees of deterioration and impairment. CONCLUSION The same ABCA4 mutation can lead to different clinical phenotypes, and there is variation in the degree of damage to vision, visual field, and electrophysiology among different clinical phenotypes. Clinicians must differentiate between and diagnose pathologies resulting from this mutation.
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Affiliation(s)
- Xuan Xiao
- Eye Center, Renmin Hospital of Wuhan University, Wuhan University, Hubei, Wuhan 430060, China
| | - Lin Ye
- Department of Eye Plastic and Lacrimal Diseases, Shenzhen Eye Hospital, Shenzhen, China
| | - Changzheng Chen
- Eye Center, Renmin Hospital of Wuhan University, Wuhan University, Hubei, Wuhan 430060, China
| | - Hongmei Zheng
- Eye Center, Renmin Hospital of Wuhan University, Wuhan University, Hubei, Wuhan 430060, China
| | - Jiajia Yuan
- Eye Center, Renmin Hospital of Wuhan University, Wuhan University, Hubei, Wuhan 430060, China
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25
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Schellens R, de Vrieze E, Slijkerman R, Kremer H, van Wijk E. Generation of Humanized Zebrafish Models for the In Vivo Assessment of Antisense Oligonucleotide-Based Splice Modulation Therapies. Methods Mol Biol 2022; 2434:281-299. [PMID: 35213025 PMCID: PMC9703260 DOI: 10.1007/978-1-0716-2010-6_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Antisense oligonucleotide (AON)-based splice modulation is the most widely used therapeutic approach to redirect precursor messenger RNA (pre-mRNA) splicing. To study the functional effect of human mutations affecting pre-mRNA splicing for which AON-based splice redirection would be a potential therapeutic option, humanized knock-in animal models are pivotal. A major limitation of using humanized animal models for this purpose is the reported poor recognition of human splice sites by the splicing machineries of other species. To overcome this problem, we provide a detailed guideline for the generation of functional humanized knock-in zebrafish models to assess the effect of mutation-induced aberrant splicing and subsequent AON-based splice modulation therapy .
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Affiliation(s)
- Renske Schellens
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Erik de Vrieze
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Ralph Slijkerman
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
| | - Hannie Kremer
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Radboud University Medical Center, Nijmegen, The Netherlands.
- Donders Institute for Brain Cognition and Behaviour, Nijmegen, The Netherlands.
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26
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Molday RS, Garces FA, Scortecci JF, Molday LL. Structure and function of ABCA4 and its role in the visual cycle and Stargardt macular degeneration. Prog Retin Eye Res 2021; 89:101036. [PMID: 34954332 DOI: 10.1016/j.preteyeres.2021.101036] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 12/07/2021] [Accepted: 12/13/2021] [Indexed: 12/17/2022]
Abstract
ABCA4 is a member of the superfamily of ATP-binding cassette (ABC) transporters that is preferentially localized along the rim region of rod and cone photoreceptor outer segment disc membranes. It uses the energy from ATP binding and hydrolysis to transport N-retinylidene-phosphatidylethanolamine (N-Ret-PE), the Schiff base adduct of retinal and phosphatidylethanolamine, from the lumen to the cytoplasmic leaflet of disc membranes. This ensures that all-trans-retinal and excess 11-cis-retinal are efficiently cleared from photoreceptor cells thereby preventing the accumulation of toxic retinoid compounds. Loss-of-function mutations in the gene encoding ABCA4 cause autosomal recessive Stargardt macular degeneration, also known as Stargardt disease (STGD1), and related autosomal recessive retinopathies characterized by impaired central vision and an accumulation of lipofuscin and bis-retinoid compounds. High resolution structures of ABCA4 in its substrate and nucleotide free state and containing bound N-Ret-PE or ATP have been determined by cryo-electron microscopy providing insight into the molecular architecture of ABCA4 and mechanisms underlying substrate recognition and conformational changes induced by ATP binding. The expression and functional characterization of a large number of disease-causing missense ABCA4 variants have been determined. These studies have shed light into the molecular mechanisms underlying Stargardt disease and a classification that reliably predicts the effect of a specific missense mutation on the severity of the disease. They also provide a framework for developing rational therapeutic treatments for ABCA4-associated diseases.
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Affiliation(s)
- Robert S Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada; Department of Ophthalmology & Visual Sciences, University of British Columbia, Vancouver, B.C., Canada.
| | - Fabian A Garces
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
| | | | - Laurie L Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, B.C., Canada
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27
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Lee W, Zernant J, Su PY, Nagasaki T, Tsang SH, Allikmets R. A genotype-phenotype correlation matrix for Stargardt/ABCA4 disease based on long-term prognostic outcomes. JCI Insight 2021; 7:156154. [PMID: 34874912 PMCID: PMC8855796 DOI: 10.1172/jci.insight.156154] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 12/01/2021] [Indexed: 11/26/2022] Open
Abstract
Background More than 1500 variants in the ATP-binding cassette, sub-family A, member 4 (ABCA4), locus underlie a heterogeneous spectrum of retinal disorders ranging from aggressive childhood-onset chorioretinopathy to milder late-onset macular disease. Genotype-phenotype correlation studies have been limited in clinical applicability as patient cohorts are typically small and seldom capture the full natural history of individual genotypes. To overcome these limitations, we constructed a genotype-phenotype correlation matrix that provides quantifiable probabilities of long-term disease outcomes associated with specific ABCA4 genotypes from a large, age-restricted patient cohort. Methods The study included 112 unrelated patients at least 50 years of age in whom 2 pathogenic variants were identified after sequencing of the ABCA4 locus. Clinical characterization was performed using the results of best corrected visual acuity, retinal imaging, and full-field electroretinogram testing. Results Four distinct prognostic groups were defined according to the spatial severity of disease features across the fundus. Recurring genotypes were observed in milder prognoses, including a newly defined class of rare hypomorphic alleles. PVS1 (predicted null) variants were enriched in the most severe prognoses; however, missense variants were present in a larger-than-expected fraction of these patients. Analysis of allele combinations and their respective prognostic severity showed that certain variants, such as p.(Gly1961Glu), and both rare and frequent hypomorphic alleles, were “clinically dominant” with respect to patient phenotypes irrespective of the allele in trans. Conclusion These results provide much-needed structure to the complex genetic and clinical landscape of ABCA4 disease and add a tool to the clinical repertoire to quantitatively assess individual genotype-specific prognoses in patients. FUNDING National Eye Institute, NIH, grants R01 EY028203, R01 EY028954, R01 EY029315, P30 19007 (Core Grant for Vision Research); the Foundation Fighting Blindness USA, grant no. PPA-1218-0751-COLU; and Research to Prevent Blindness.
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Affiliation(s)
- Winston Lee
- Department of Genetics and Development, Columbia University Irving Medical Center, New York, United States of America
| | - Jana Zernant
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, United States of America
| | - Pei-Yin Su
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, United States of America
| | - Takayuki Nagasaki
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, United States of America
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, United States of America
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University Irving Medical Center, New York, United States of America
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28
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Della Volpe Waizel M, Scholl HPN, Todorova MG. Microvascular and metabolic alterations in retinitis pigmentosa and Stargardt disease. Acta Ophthalmol 2021; 99:e1396-e1404. [PMID: 33973369 DOI: 10.1111/aos.14828] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 12/14/2022]
Abstract
PURPOSE The aim of our study was to evaluate retinal microvascular changes recorded with optical coherence tomography angiography (OCTA) and the metabolic function measured with retinal oximetry (RO) in patients with retinitis pigmentosa (RP) and Stargardt disease (STGD). METHODS In this prospective, noninterventional study, OCTA and RO were performed on 107 eyes (56 subjects): 53 eyes diagnosed with RP without the presence of macular oedema (no-ME-RP), 26 eyes with STGD, and 28 control eyes. Main outcome measures were the mean superficial (FAZ-S; mm2 ) and deep foveal avascular zone (FAZ-D; mm2 ) measured with OCTA as well as the mean arterial (A-SO2 ; %), venular (V-SO2 ; %) oxygen saturation, their difference (A-V SO2 ; %) and the corresponding mean diameters of the peripapillary retinal arterioles (D-A; μm) and venules (D-V; μm) determined with RO. RESULTS Stargardt disease (STGD) patients differed from controls and no-ME-RP by an enlarged FAZ-S and reduced A-SO2 and V-SO2 (p ≤ 0.013). No-ME-RP eyes presented with attenuated vessels (p < 0.001) and increased A-SO2 and V-SO2 (p ≤ 0.012) compared to controls and STGD. The FAZ-D showed significant interactions with A-SO2 (p = 0.003) in no-ME-RP while the FAZ-S correlated with visual acuity in no-ME-RP (p = 0.007) and STGD (p = 0.034). CONCLUSION Retinitis pigmentosa (RP) and Stargardt disease (STGD) patients suffer from microvascular and metabolic alterations, however, showing a different pattern. A combined microvascular-metabolic model may therefore allow to more precisely characterize RP and STGD as well as presumably other inherited retinal diseases.
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Affiliation(s)
| | - Hendrik P. N. Scholl
- Department of Ophthalmology University of Basel Basel Switzerland
- Institute of Molecular and Clinical Ophthalmology Basel (IOB) Basel Switzerland
| | - Margarita G. Todorova
- Department of Ophthalmology University of Basel Basel Switzerland
- Department of Ophthalmology Cantonal Hospital St. Gallen St. Gallen Switzerland
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29
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Schneider N, Sundaresan Y, Gopalakrishnan P, Beryozkin A, Hanany M, Levanon EY, Banin E, Ben-Aroya S, Sharon D. Inherited retinal diseases: Linking genes, disease-causing variants, and relevant therapeutic modalities. Prog Retin Eye Res 2021; 89:101029. [PMID: 34839010 DOI: 10.1016/j.preteyeres.2021.101029] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/11/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically complex and heterogenous group of visual impairment phenotypes caused by pathogenic variants in at least 277 nuclear and mitochondrial genes, affecting different retinal regions, and depleting the vision of affected individuals. Genes that cause IRDs when mutated are unique by possessing differing genotype-phenotype correlations, varying inheritance patterns, hypomorphic alleles, and modifier genes thus complicating genetic interpretation. Next-generation sequencing has greatly advanced the identification of novel IRD-related genes and pathogenic variants in the last decade. For this review, we performed an in-depth literature search which allowed for compilation of the Global Retinal Inherited Disease (GRID) dataset containing 4,798 discrete variants and 17,299 alleles published in 31 papers, showing a wide range of frequencies and complexities among the 194 genes reported in GRID, with 65% of pathogenic variants being unique to a single individual. A better understanding of IRD-related gene distribution, gene complexity, and variant types allow for improved genetic testing and therapies. Current genetic therapeutic methods are also quite diverse and rely on variant identification, and range from whole gene replacement to single nucleotide editing at the DNA or RNA levels. IRDs and their suitable therapies thus require a range of effective disease modelling in human cells, granting insight into disease mechanisms and testing of possible treatments. This review summarizes genetic and therapeutic modalities of IRDs, provides new analyses of IRD-related genes (GRID and complexity scores), and provides information to match genetic-based therapies such as gene-specific and variant-specific therapies to the appropriate individuals.
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Affiliation(s)
- Nina Schneider
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Yogapriya Sundaresan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Prakadeeswari Gopalakrishnan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Avigail Beryozkin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Mor Hanany
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Erez Y Levanon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Shay Ben-Aroya
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel.
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30
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Fadaie Z, Whelan L, Ben-Yosef T, Dockery A, Corradi Z, Gilissen C, Haer-Wigman L, Corominas J, Astuti GDN, de Rooij L, van den Born LI, Klaver CCW, Hoyng CB, Wynne N, Duignan ES, Kenna PF, Cremers FPM, Farrar GJ, Roosing S. Whole genome sequencing and in vitro splice assays reveal genetic causes for inherited retinal diseases. NPJ Genom Med 2021; 6:97. [PMID: 34795310 PMCID: PMC8602293 DOI: 10.1038/s41525-021-00261-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Accepted: 10/21/2021] [Indexed: 01/08/2023] Open
Abstract
Inherited retinal diseases (IRDs) are a major cause of visual impairment. These clinically heterogeneous disorders are caused by pathogenic variants in more than 270 genes. As 30-40% of cases remain genetically unexplained following conventional genetic testing, we aimed to obtain a genetic diagnosis in an IRD cohort in which the genetic cause was not found using whole-exome sequencing or targeted capture sequencing. We performed whole-genome sequencing (WGS) to identify causative variants in 100 unresolved cases. After initial prioritization, we performed an in-depth interrogation of all noncoding and structural variants in genes when one candidate variant was detected. In addition, functional analysis of putative splice-altering variants was performed using in vitro splice assays. We identified the genetic cause of the disease in 24 patients. Causative coding variants were observed in genes such as ATXN7, CEP78, EYS, FAM161A, and HGSNAT. Gene disrupting structural variants were also detected in ATXN7, PRPF31, and RPGRIP1. In 14 monoallelic cases, we prioritized candidate noncanonical splice sites or deep-intronic variants that were predicted to disrupt the splicing process based on in silico analyses. Of these, seven cases were resolved as they carried pathogenic splice defects. WGS is a powerful tool to identify causative variants residing outside coding regions or heterozygous structural variants. This approach was most efficient in cases with a distinct clinical diagnosis. In addition, in vitro splice assays provide important evidence of the pathogenicity of rare variants.
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Affiliation(s)
- Zeinab Fadaie
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laura Whelan
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Tamar Ben-Yosef
- Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Adrian Dockery
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Zelia Corradi
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lonneke Haer-Wigman
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jordi Corominas
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Galuh D N Astuti
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Division of Human Genetics, Center for Biomedical Research (CEBIOR), Faculty of Medicine, Diponegoro University, Semarang, Indonesia
| | - Laura de Rooij
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carel B Hoyng
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Niamh Wynne
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Emma S Duignan
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Paul F Kenna
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Department of Ophthalmology, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - G Jane Farrar
- The School of Genetics and Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Susanne Roosing
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
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31
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Fars J, Pasutto F, Kremers J, Huchzermeyer C. Perifoveal Cone- and Rod-Mediated Temporal Contrast Sensitivities in Stargardt Disease/Fundus Flavimaculatus. Invest Ophthalmol Vis Sci 2021; 62:24. [PMID: 34807235 PMCID: PMC8626853 DOI: 10.1167/iovs.62.14.24] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to compare L-cone-driven, S-cone-driven, and rod-driven temporal contrast sensitivities (tCSs) in patients with Stargardt disease 1/fundus flavimaculatus (STGD1/FF). Methods Fourteen patients (eight male, six female; mean age, 43.21 ± 13.18 years) with genetically confirmed STGD1/FF participated in this study. A dedicated light-emitting diode stimulator was used to measure perifoveal tCSs in an annular test field (1°-6° of visual eccentricity) at temporal frequencies between 1 and 20 Hz. Photoreceptor classes were isolated with the triple silent substitution technique. To compare functional damage among photoreceptor classes, sensitivity deviations (decibels) were calculated based on age-related normal values and then averaged across those frequencies where perception is mediated by the same post-receptoral pathway (L-cone red-green opponent pathway: 1, 2, 4 Hz; luminance pathway: 12, 16, 20 Hz; S-cone pathway: 1, 2, 4 Hz; fast rod pathway: 8, 10, 12 Hz). Sensitivity deviations were compared with infrared scanning laser ophthalmoscopy (IR-SLO) and standard automated perimetry (SAP). Results Photoreceptor-driven tCSs were generally lower in patients with STGD1/FF than in normal subjects but were without systematic differences among photoreceptors. Although sensitivity deviations were significantly correlated between each other, only luminance-driven L-cone sensitivity deviations were significantly correlated with the IR-SLO area of hyporeflectance (AoH) and SAP central mean deviation within 6° eccentricity (MD6deg). Conclusions No systematic differences between photoreceptor classes were detected; however, our data suggest that temporal contrasts detected by the luminance pathway were closely correlated with other clinical parameters (AoH and MD6deg) and might be most useful as functional biomarkers in clinical trials.
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Affiliation(s)
- Julien Fars
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Francesca Pasutto
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Jan Kremers
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - Cord Huchzermeyer
- Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
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32
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Lofaro FD, Mucciolo DP, Murro V, Pavese L, Quaglino D, Boraldi F. A Case Report of Pseudoxanthoma Elasticum with Rare Sequence Variants in Genes Related to Inherited Retinal Diseases. Diagnostics (Basel) 2021; 11:diagnostics11101800. [PMID: 34679498 PMCID: PMC8534466 DOI: 10.3390/diagnostics11101800] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 01/11/2023] Open
Abstract
A case of a patient with an early and severe visual impairment is described. Due to the occurrence of skin papules a suspect of pseudoxanthoma elasticum (PXE) was posed. PXE is a rare autosomal recessive disease clinically characterized by skin, cardiovascular and ocular manifestations, these last being those that most severely affect patients’ quality of life. A whole exome sequencing approach focusing on 340 genes related to the calcification process and/or to inherited retinal diseases (IRDs) was performed. Rare monoallelic sequence variants in ABCA4, ABCC6, IMPG1, POC1B and RAX2 were found. The presence of calcified elastic fibers was assessed by ultrastructural analysis on a skin biopsy. Diagnosis of PXE was based on clinical, biomolecular and morphological results, although the additional involvement of several IRD genes is important to explain the unexpectedly severe ophthalmological phenotype of the patient also in prognostic and therapeutic perspectives. Data indicate that genetic screening using a wide-spectrum analysis approach is essential to assist ophthalmologists in improving patient counseling.
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Affiliation(s)
- Francesco Demetrio Lofaro
- Department of Life Science, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
| | - Dario Pasquale Mucciolo
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, 50139 Florence, Italy; (D.P.M.); (V.M.); (L.P.)
| | - Vittoria Murro
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, 50139 Florence, Italy; (D.P.M.); (V.M.); (L.P.)
| | - Laura Pavese
- Department of Neuroscience, Psychology, Drug Research and Child Health, University of Florence, Eye Clinic, 50139 Florence, Italy; (D.P.M.); (V.M.); (L.P.)
| | - Daniela Quaglino
- Department of Life Science, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
| | - Federica Boraldi
- Department of Life Science, University of Modena and Reggio Emilia, 41125 Modena, Italy; (F.D.L.); (D.Q.)
- Correspondence:
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Huang D, Heath Jeffery RC, Aung-Htut MT, McLenachan S, Fletcher S, Wilton SD, Chen FK. Stargardt disease and progress in therapeutic strategies. Ophthalmic Genet 2021; 43:1-26. [PMID: 34455905 DOI: 10.1080/13816810.2021.1966053] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Background: Stargardt disease (STGD1) is an autosomal recessive retinal dystrophy due to mutations in ABCA4, characterized by subretinal deposition of lipofuscin-like substances and bilateral centrifugal vision loss. Despite the tremendous progress made in the understanding of STGD1, there are no approved treatments to date. This review examines the challenges in the development of an effective STGD1 therapy.Materials and Methods: A literature review was performed through to June 2021 summarizing the spectrum of retinal phenotypes in STGD1, the molecular biology of ABCA4 protein, the in vivo and in vitro models used to investigate the mechanisms of ABCA4 mutations and current clinical trials.Results: STGD1 phenotypic variability remains an challenge for clinical trial design and patient selection. Pre-clinical development of therapeutic options has been limited by the lack of animal models reflecting the diverse phenotypic spectrum of STDG1. Patient-derived cell lines have facilitated the characterization of splice mutations but the clinical presentation is not always predicted by the effect of specific mutations on retinoid metabolism in cellular models. Current therapies primarily aim to delay vision loss whilst strategies to restore vision are less well developed.Conclusions: STGD1 therapy development can be accelerated by a deeper understanding of genotype-phenotype correlations.
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Affiliation(s)
- Di Huang
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Murdoch University, Western Australia, Australia.,Perron Institute for Neurological and Translational Science & the University of Western Australia, Nedlands, Western Australia, Australia
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), the University of Western Australia, Nedlands, Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia.,Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
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Al-Khuzaei S, Broadgate S, Foster CR, Shah M, Yu J, Downes SM, Halford S. An Overview of the Genetics of ABCA4 Retinopathies, an Evolving Story. Genes (Basel) 2021; 12:1241. [PMID: 34440414 PMCID: PMC8392661 DOI: 10.3390/genes12081241] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 11/16/2022] Open
Abstract
Stargardt disease (STGD1) and ABCA4 retinopathies (ABCA4R) are caused by pathogenic variants in the ABCA4 gene inherited in an autosomal recessive manner. The gene encodes an importer flippase protein that prevents the build-up of vitamin A derivatives that are toxic to the RPE. Diagnosing ABCA4R is complex due to its phenotypic variability and the presence of other inherited retinal dystrophy phenocopies. ABCA4 is a large gene, comprising 50 exons; to date > 2000 variants have been described. These include missense, nonsense, splicing, structural, and deep intronic variants. Missense variants account for the majority of variants in ABCA4. However, in a significant proportion of patients with an ABCA4R phenotype, a second variant in ABCA4 is not identified. This could be due to the presence of yet unknown variants, or hypomorphic alleles being incorrectly classified as benign, or the possibility that the disease is caused by a variant in another gene. This underlines the importance of accurate genetic testing. The pathogenicity of novel variants can be predicted using in silico programs, but these rely on databases that are not ethnically diverse, thus highlighting the need for studies in differing populations. Functional studies in vitro are useful towards assessing protein function but do not directly measure the flippase activity. Obtaining an accurate molecular diagnosis is becoming increasingly more important as targeted therapeutic options become available; these include pharmacological, gene-based, and cell replacement-based therapies. The aim of this review is to provide an update on the current status of genotyping in ABCA4 and the status of the therapeutic approaches being investigated.
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Affiliation(s)
- Saoud Al-Khuzaei
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Suzanne Broadgate
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | | | - Mital Shah
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
| | - Jing Yu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Susan M. Downes
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (S.A.-K.); (M.S.)
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK; (S.B.); (J.Y.)
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Holtan JP, Aukrust I, Jansson RW, Berland S, Bruland O, Gjerde BL, Stokowy T, Bojovic O, Forsaa V, Austeng D, Rødahl E, Bredrup C, Knappskog PM, Bragadóttir R. Clinical features and molecular genetics of patients with ABCA4-retinal dystrophies. Acta Ophthalmol 2021; 99:e733-e746. [PMID: 33258285 DOI: 10.1111/aos.14679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/29/2020] [Accepted: 10/17/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Pathogenic variations in the ABCA4 gene are a leading cause of vision loss in patients with inherited retinal diseases. ABCA4-retinal dystrophies are clinically heterogeneous, presenting with mild to severe degeneration of the retina. The purpose of this study was to clinically and genetically characterize patients with ABCA4-retinal dystrophies in Norway and describe phenotype-genotype associations. METHODS ABCA4 variants were detected in 111 patients with inherited retinal disease undergoing diagnostic genetic testing over a period of 12 years. In patients where only a single ABCA4 variant was found, whole-gene ABCA4 sequencing was performed and intronic variants were investigated by mRNA analyses in fibroblasts. Medical journals were used to obtain a clinical description and ultrawidefield autofluorescence images were used to analyse retinal degeneration patterns. RESULTS The genetic diagnostic yield was 89%. The intronic splice variant c.5461-10T>C was the most prevalent disease-causing variant (27%). Whole-gene ABCA4 sequencing detected two novel intronic variants (c.6729+81G>T and c.6817-679C>A) that we showed affected mRNA splicing. Peripheral retinal degeneration was identified in 33% of patients and was associated with genotypes that included severe loss of function variants. By contrast, peripheral degeneration was not found in patients with a disease duration over 20 years and genotypes including p.(Asn1868lle), c.4253+43G>A or p.(Gly1961Glu) in trans with a loss of function variant. CONCLUSION This study demonstrates the clinical and genetic heterogeneity of ABCA4-retinal dystrophies in Norway. Further, the study presents novel variants and increases our knowledge on phenotype-genotype associations and the presence of peripheral retinal degeneration in ABCA4-retinal dystrophy patients.
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Affiliation(s)
- Josephine Prener Holtan
- Department of Ophthalmology Oslo University Hospital Oslo Norway
- Institute of Clinical Medicine University of Oslo Oslo Norway
| | - Ingvild Aukrust
- Department of Medical Genetics Haukeland University Hospital Bergen Norway
- Department of Clinical Science University of Bergen Bergen Norway
| | | | - Siren Berland
- Department of Medical Genetics Haukeland University Hospital Bergen Norway
| | - Ove Bruland
- Department of Medical Genetics Haukeland University Hospital Bergen Norway
| | | | - Tomasz Stokowy
- Genomics Core Facility Department of Clinical Science University of Bergen Bergen Norway
| | - Ognjen Bojovic
- Department of Medical Genetics Haukeland University Hospital Bergen Norway
| | - Vegard Forsaa
- Department of Ophthalmology Stavanger University Hospital Stavanger Norway
| | - Dordi Austeng
- Department of Ophthalmology St. Olav University Hospital Trondheim Norway
| | - Eyvind Rødahl
- Department of Ophthalmology Haukeland University Hospital Bergen Norway
- Department of Clinical Medicine University of Bergen Bergen Norway
| | - Cecilie Bredrup
- Department of Ophthalmology Haukeland University Hospital Bergen Norway
- Department of Clinical Medicine University of Bergen Bergen Norway
| | - Per Morten Knappskog
- Department of Medical Genetics Haukeland University Hospital Bergen Norway
- Department of Clinical Science University of Bergen Bergen Norway
| | - Ragnheiður Bragadóttir
- Department of Ophthalmology Oslo University Hospital Oslo Norway
- Institute of Clinical Medicine University of Oslo Oslo Norway
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García Bohórquez B, Aller E, Rodríguez Muñoz A, Jaijo T, García García G, Millán JM. Updating the Genetic Landscape of Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:645600. [PMID: 34327195 PMCID: PMC8315279 DOI: 10.3389/fcell.2021.645600] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 04/30/2021] [Indexed: 12/24/2022] Open
Abstract
Inherited retinal dystrophies (IRD) are a group of diseases characterized by the loss or dysfunction of photoreceptors and a high genetic and clinical heterogeneity. Currently, over 270 genes have been associated with IRD which makes genetic diagnosis very difficult. The recent advent of next generation sequencing has greatly facilitated the diagnostic process, enabling to provide the patients with accurate genetic counseling in some cases. We studied 92 patients who were clinically diagnosed with IRD with two different custom panels. In total, we resolved 53 patients (57.6%); in 12 patients (13%), we found only one mutation in a gene with a known autosomal recessive pattern of inheritance; and 27 patients (29.3%) remained unsolved. We identified 120 pathogenic or likely pathogenic variants; 30 of them were novel. Among the cone-rod dystrophy patients, ABCA4 was the most common mutated gene, meanwhile, USH2A was the most prevalent among the retinitis pigmentosa patients. Interestingly, 10 families carried pathogenic variants in more than one IRD gene, and we identified two deep-intronic variants previously described as pathogenic in ABCA4 and CEP290. In conclusion, the IRD study through custom panel sequencing demonstrates its efficacy for genetic diagnosis, as well as the importance of including deep-intronic regions in their design. This genetic diagnosis will allow patients to make accurate reproductive decisions, enroll in gene-based clinical trials, and benefit from future gene-based treatments.
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Affiliation(s)
- Belén García Bohórquez
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
| | - Elena Aller
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
- Unit of Genetics, University Hospital La Fe, Valencia, Spain
| | - Ana Rodríguez Muñoz
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
| | - Teresa Jaijo
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
- Unit of Genetics, University Hospital La Fe, Valencia, Spain
| | - Gema García García
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
| | - José M. Millán
- Molecular, Cellular and Genomics Biomedicine, Health Research Institute La Fe, Valencia, Spain
- CIBER of Rare Diseases, Madrid, Spain
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Mullin NK, Voigt AP, Cooke JA, Bohrer LR, Burnight ER, Stone EM, Mullins RF, Tucker BA. Patient derived stem cells for discovery and validation of novel pathogenic variants in inherited retinal disease. Prog Retin Eye Res 2021; 83:100918. [PMID: 33130253 PMCID: PMC8559964 DOI: 10.1016/j.preteyeres.2020.100918] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 02/07/2023]
Abstract
Our understanding of inherited retinal disease has benefited immensely from molecular genetic analysis over the past several decades. New technologies that allow for increasingly detailed examination of a patient's DNA have expanded the catalog of genes and specific variants that cause retinal disease. In turn, the identification of pathogenic variants has allowed the development of gene therapies and low-cost, clinically focused genetic testing. Despite this progress, a relatively large fraction (at least 20%) of patients with clinical features suggestive of an inherited retinal disease still do not have a molecular diagnosis today. Variants that are not obviously disruptive to the codon sequence of exons can be difficult to distinguish from the background of benign human genetic variations. Some of these variants exert their pathogenic effect not by altering the primary amino acid sequence, but by modulating gene expression, isoform splicing, or other transcript-level mechanisms. While not discoverable by DNA sequencing methods alone, these variants are excellent targets for studies of the retinal transcriptome. In this review, we present an overview of the current state of pathogenic variant discovery in retinal disease and identify some of the remaining barriers. We also explore the utility of new technologies, specifically patient-derived induced pluripotent stem cell (iPSC)-based modeling, in further expanding the catalog of disease-causing variants using transcriptome-focused methods. Finally, we outline bioinformatic analysis techniques that will allow this new method of variant discovery in retinal disease. As the knowledge gleaned from previous technologies is informing targets for therapies today, we believe that integrating new technologies, such as iPSC-based modeling, into the molecular diagnosis pipeline will enable a new wave of variant discovery and expanded treatment of inherited retinal disease.
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Affiliation(s)
- Nathaniel K Mullin
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Andrew P Voigt
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Jessica A Cooke
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Laura R Bohrer
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Erin R Burnight
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Edwin M Stone
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert F Mullins
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Budd A Tucker
- The Institute for Vision Research, University of Iowa, Iowa City, IA, USA; Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA.
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Riepe TV, Khan M, Roosing S, Cremers FPM, 't Hoen PAC. Benchmarking deep learning splice prediction tools using functional splice assays. Hum Mutat 2021; 42:799-810. [PMID: 33942434 PMCID: PMC8360004 DOI: 10.1002/humu.24212] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 03/16/2021] [Accepted: 04/17/2021] [Indexed: 12/21/2022]
Abstract
Hereditary disorders are frequently caused by genetic variants that affect pre-messenger RNA splicing. Though genetic variants in the canonical splice motifs are almost always disrupting splicing, the pathogenicity of variants in the noncanonical splice sites (NCSS) and deep intronic (DI) regions are difficult to predict. Multiple splice prediction tools have been developed for this purpose, with the latest tools employing deep learning algorithms. We benchmarked established and deep learning splice prediction tools on published gold standard sets of 71 NCSS and 81 DI variants in the ABCA4 gene and 61 NCSS variants in the MYBPC3 gene with functional assessment in midigene and minigene splice assays. The selection of splice prediction tools included CADD, DSSP, GeneSplicer, MaxEntScan, MMSplice, NNSPLICE, SPIDEX, SpliceAI, SpliceRover, and SpliceSiteFinder-like. The best-performing splice prediction tool for the different variants was SpliceRover for ABCA4 NCSS variants, SpliceAI for ABCA4 DI variants, and the Alamut 3/4 consensus approach (GeneSplicer, MaxEntScacn, NNSPLICE and SpliceSiteFinder-like) for NCSS variants in MYBPC3 based on the area under the receiver operator curve. Overall, the performance in a real-time clinical setting is much more modest than reported by the developers of the tools.
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Affiliation(s)
- Tabea V. Riepe
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Mubeen Khan
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Susanne Roosing
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Frans P. M. Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and BehaviorRadboud University Medical CenterNijmegenThe Netherlands
| | - Peter A. C. 't Hoen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life SciencesRadboud University Medical CenterNijmegenThe Netherlands
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Huang D, Zhang D, Chen SC, Aung-Htut MT, Lamey TM, Thompson JA, McLaren TL, De Roach JN, Fletcher S, Wilton SD, Chen FK, McLenachan S. Generation of two induced pluripotent stem cell lines from a patient with Stargardt disease caused by compound heterozygous mutations in the ABCA4 gene. Stem Cell Res 2021; 54:102448. [PMID: 34198153 DOI: 10.1016/j.scr.2021.102448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 06/21/2021] [Indexed: 11/30/2022] Open
Abstract
Stargardt disease (STGD1) is the most common inherited retinal dystrophy and ABCA4 c.546--10 T>C is the most commonly reported splice mutation. Here, we generated and characterized two induced pluripotent stem cell (iPSC) lines from a STGD1 patient with compound heterozygous mutations in ABCA4 (c.[5461-10 T > C;5603A > T];[4163 T > C;455G > A]). Episomal vectors containing OCT4, SOX2, KLF4, L-MYC, LIN28 and mp53DD were employed to conduct the reprogramming of patient-derived fibroblasts. Both lines had a normal karyotype, displayed iPSC morphology, expressed pluripotency markers and showed trilineage differentiation potential. These lines can provide a powerful platform for further investigating the pathophysiological consequences of mutations in ABCA4.
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Affiliation(s)
- Di Huang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Dan Zhang
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Shang-Chih Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - May Thandar Aung-Htut
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Terri L McLaren
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - John N De Roach
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Sue Fletcher
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia
| | - Steve D Wilton
- Centre for Molecular Medicine and Innovative Therapeutics, Health Futures Institute, Murdoch University, Western Australia, Australia; Perron Institute for Neurological and Translational Science, Centre for Neuromuscular and Neurological Disorders, The University of Western Australia, Australia
| | - Fred K Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia; Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia; Department of Ophthalmology, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Ophthalmology, Perth Children's Hospital, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia; Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, Western Australia, Australia.
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Structural basis of substrate recognition and translocation by human ABCA4. Nat Commun 2021; 12:3853. [PMID: 34158497 PMCID: PMC8219669 DOI: 10.1038/s41467-021-24194-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 06/04/2021] [Indexed: 12/29/2022] Open
Abstract
Human ATP-binding cassette (ABC) subfamily A (ABCA) transporters mediate the transport of various lipid compounds across the membrane. Mutations in human ABCA transporters have been described to cause severe hereditary disorders associated with impaired lipid transport. However, little is known about the mechanistic details of substrate recognition and translocation by ABCA transporters. Here, we present three cryo-EM structures of human ABCA4, a retina-specific ABCA transporter, in distinct functional states at resolutions of 3.3–3.4 Å. In the nucleotide-free state, the two transmembrane domains (TMDs) exhibit a lateral-opening conformation, allowing the lateral entry of substrate from the lipid bilayer. The N-retinylidene-phosphatidylethanolamine (NRPE), the physiological lipid substrate of ABCA4, is sandwiched between the two TMDs in the luminal leaflet and is further stabilized by an extended loop from extracellular domain 1. In the ATP-bound state, the two TMDs display a closed conformation, which precludes the substrate binding. Our study provides a molecular basis to understand the mechanism of ABCA4-mediated NRPE recognition and translocation, and suggests a common ‘lateral access and extrusion’ mechanism for ABCA-mediated lipid transport. Here, cryo-EM structures of human retinal ABCA4 transporter, either in apo state, in complex with ATP or with the physiological lipid substrate N-retinylidene-phosphatidylethanolamine (NRPE), reveal lateral opening, substrate recognition and suggest ‘lateral access and extrusion’ mechanism for ABCA-mediated lipid transport.
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Absence of Genotype/Phenotype Correlations Requires Molecular Diagnostic to Ascertain Stargardt and Stargardt-Like Swiss Patients. Genes (Basel) 2021; 12:genes12060812. [PMID: 34073554 PMCID: PMC8229718 DOI: 10.3390/genes12060812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 11/25/2022] Open
Abstract
We genetically characterized 22 Swiss patients who had been diagnosed with Stargardt disease after clinical examination. We identified in 11 patients (50%) pathogenic bi-allelic ABCA4 variants, c.1760+2T>C and c.4496T>C being novel. The dominantly inherited pathogenic ELOVL4 c.810C>G p.(Tyr270*) and PRPH2-c.422A>G p.(Tyr141Cys) variants were identified in eight (36%) and three patients (14%), respectively. All patients harboring the ELOVL4 c.810C>G p.(Tyr270*) variant originated from the same small Swiss area, identifying a founder mutation. In the ABCA4 and ELOVL4 cohorts, the clinical phenotypes of “flecks”, “atrophy”, and “bull’s eye like” were observed by fundus examination. In the small number of patients harboring the pathogenic PRPH2 variant, we could observe both “flecks” and “atrophy” clinical phenotypes. The onset of disease, progression of visual acuity and clinical symptoms, inheritance patterns, fundus autofluorescence, and optical coherence tomography did not allow discrimination between the genetically heterogeneous Stargardt patients. The genetic heterogeneity observed in the relatively small Swiss population should prompt systematic genetic testing of clinically diagnosed Stargardt patients. The resulting molecular diagnostic is required to prevent potentially harmful vitamin A supplementation, to provide genetic counseling with respect to inheritance, and to schedule appropriate follow-up visits in the presence of increased risk of choroidal neovascularization.
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Li J, Du W, Xu N, Tao T, Tang X, Huang L. RNA-seq analysis for exploring the pathogenesis of Retinitis pigmentosa in P23H knock-in mice. Ophthalmic Res 2021; 64:798-810. [PMID: 33971646 DOI: 10.1159/000515727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Accepted: 03/05/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Jiarui Li
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China,
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China,
- College of Optometry, Peking University Health Science Center, Beijing, China,
| | - Wei Du
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Ningda Xu
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Tianchang Tao
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Xin Tang
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
| | - Lvzhen Huang
- Eye diseases and Optometry Institute, Department of Ophthalmology, Peking University People's Hospital, Beijing, China
- Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases, Beijing, China
- College of Optometry, Peking University Health Science Center, Beijing, China
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Lee W, Zernant J, Nagasaki T, Molday LL, Su PY, Fishman GA, Tsang SH, Molday RS, Allikmets R. Cis-acting modifiers in the ABCA4 locus contribute to the penetrance of the major disease-causing variant in Stargardt disease. Hum Mol Genet 2021; 30:1293-1304. [PMID: 33909047 DOI: 10.1093/hmg/ddab122] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 04/01/2021] [Accepted: 04/20/2021] [Indexed: 11/14/2022] Open
Abstract
Over 1200 variants in the ABCA4 gene cause a wide variety of retinal disease phenotypes, the best known of which is autosomal recessive Stargardt disease (STGD1). Disease-causing variation encompasses all mutation categories, from large copy number variants to very mild, hypomorphic missense variants. The most prevalent disease-causing ABCA4 variant, present in ~ 20% of cases of European descent, c.5882G > A p.(Gly1961Glu), has been a subject of controversy since its minor allele frequency (MAF) is as high as ~ 0.1 in certain populations, questioning its pathogenicity, especially in homozygous individuals. We sequenced the entire ~140Kb ABCA4 genomic locus in an extensive cohort of 644 bi-allelic, i.e. genetically confirmed, patients with ABCA4 disease and analyzed all variants in 140 compound heterozygous and 10 homozygous cases for the p.(Gly1961Glu) variant. A total of 23 patients in this cohort additionally harbored the deep intronic c.769-784C > T variant on the p.(Gly1961Glu) allele, which appears on a specific haplotype in ~ 15% of p.(Gly1961Glu) alleles. This haplotype was present in 5/7 of homozygous cases, where the p.(Gly1961Glu) was the only known pathogenic variant. Three cases had an exonic variant on the same allele with the p.(Gly1961Glu). Patients with the c.[769-784C > T;5882G > A] complex allele exhibit a more severe clinical phenotype, as seen in compound heterozygotes with some more frequent ABCA4 mutations, e.g. p.(Pro1380Leu). Our findings indicate that the c.769-784C > T variant is major cis-acting modifier of the p.(Gly1961Glu) allele. The absence of such additional allelic variation on most p.(Gly1961Glu) alleles largely explains the observed paucity of affected homozygotes in the population.
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Affiliation(s)
- Winston Lee
- Department of Genetics & Development, Columbia University, New York, NY 10032, USA
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
| | - Jana Zernant
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
| | - Takayuki Nagasaki
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Pei-Yin Su
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
| | - Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- The Pangere Center for Inherited Retinal Diseases, The Chicago Lighthouse, Chicago, IL 60608, USA
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
- Department of Pathology & Cell Biology, Columbia University, New York, NY 10032, USA
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY 10032, USA
- Department of Pathology & Cell Biology, Columbia University, New York, NY 10032, USA
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44
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Fadaie Z, Whelan L, Dockery A, Li CHZ, van den Born LI, Hoyng CB, Gilissen C, Corominas J, Rowlands C, Megaw R, Lampe AK, Cremers FPM, Farrar GJ, Ellingford JM, Kenna PF, Roosing S. BBS1 branchpoint variant is associated with non-syndromic retinitis pigmentosa. J Med Genet 2021; 59:438-444. [PMID: 33910932 DOI: 10.1136/jmedgenet-2020-107626] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/11/2021] [Accepted: 02/26/2021] [Indexed: 11/03/2022]
Abstract
BACKGROUND Inherited retinal diseases (IRDs) can be caused by variants in >270 genes. The Bardet-Biedl syndrome 1 (BBS1) gene is one of these genes and may be associated with syndromic and non-syndromic autosomal recessive retinitis pigmentosa (RP). Here, we identified a branchpoint variant in BBS1 and assessed its pathogenicity by in vitro functional analysis. METHODS Whole genome sequencing was performed for three unrelated monoallelic BBS1 cases with non-syndromic RP. A fourth case received MGCM 105 gene panel analysis. Functional analysis using a midigene splice assay was performed for the putative pathogenic branchpoint variant in BBS1. After confirmation of its pathogenicity, patients were clinically re-evaluated, including assessment of non-ocular features of Bardet-Biedl syndrome. RESULTS Clinical assessments of probands showed that all individuals displayed non-syndromic RP with macular involvement. Through detailed variant analysis and prioritisation, two pathogenic variants in BBS1, the most common missense variant, c.1169T>G (p.(Met390Arg)), and a branchpoint variant, c.592-21A>T, were identified. Segregation analysis confirmed that in all families, probands were compound heterozygous for c.1169T>G and c.592-21A>T. Functional analysis of the branchpoint variant revealed a complex splicing defect including exon 8 and exon 7/8 skipping, and partial in-frame deletion of exon 8. CONCLUSION A putative severe branchpoint variant in BBS1, together with a mild missense variant, underlies non-syndromic RP in four unrelated individuals. To our knowledge, this is the first report of a pathogenic branchpoint variant in IRDs that results in a complex splice defect. In addition, this research highlights the importance of the analysis of non-coding regions in order to provide a conclusive molecular diagnosis.
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Affiliation(s)
- Zeinab Fadaie
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
| | - Laura Whelan
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Adrian Dockery
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Catherina H Z Li
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | | | - Carel B Hoyng
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
- Department of Ophthalmology, Radboudumc, Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, RadboudUMC, Nijmegen, The Netherlands
| | - Jordi Corominas
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Radboud Institute of Molecular Life Sciences, RadboudUMC, Nijmegen, The Netherlands
| | - Charlie Rowlands
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, UK
- Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, The University of Manchester Faculty of Biology Medicine and Health, Manchester, UK
| | - Roly Megaw
- MRC Human Genetics Unit, University of Edinburgh Western General Hospital, Edinburgh, UK
- Princess Alexandra Eye Pavilion, Department of Ophthalmology, University of Edinburgh Western General Hospital, Edinburgh, UK
| | - Anne K Lampe
- South East of Scotland Clinical Genetics Service, Western General Hospital, Edinburgh, UK
| | - Frans P M Cremers
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
| | - Gwyneth Jane Farrar
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Jamie M Ellingford
- North West Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, Manchester University Hospitals NHS Foundation Trust, St Mary's Hospital, Manchester, UK
- Division of Evolution and Genomic Sciences, Neuroscience and Mental Health Domain, The University of Manchester Faculty of Biology Medicine and Health, Manchester, UK
| | - Paul F Kenna
- School of Genetics & Microbiology, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
- Research Foundation, Royal Victoria Eye and Ear Hospital, Dublin, Ireland
| | - Susanne Roosing
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands
- Donders Institute for Brain Cognition and Behaviour, RadboudUMC, Nijmegen, The Netherlands
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Camp DA, Gemayel MC, Ciulla TA. Understanding the genetic pathology of Stargardt disease: a review of current findings and challenges. Expert Opin Orphan Drugs 2021. [DOI: 10.1080/21678707.2021.1898373] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- David A. Camp
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Michael C. Gemayel
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Thomas A. Ciulla
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USA
- Retina Service, Midwest Eye Institute, Indianapolis, IN, USA
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46
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Al-Ani HH, Sheck L, Vincent AL. Peripheral pigmented lesions in ABCA4-associated retinopathy. Ophthalmic Genet 2021; 42:383-391. [PMID: 33706644 DOI: 10.1080/13816810.2021.1897850] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: To investigate the prevalence and characteristics of peripheral pigmented retinal lesions and the associated clinical and genetic findings in patients with pathogenic variants in the ABCA4 gene.Methods: Records at a single tertiary hospital were retrospectively reviewed to identify the presence of peripheral pigmented retinal lesions on wide-field retinal imaging in patients with ABCA4-associated disease, compared with an RDS/PRPH2 cohort, and an age-matched control group. Data on patient demographics, genetic variants, severity of disease, and phenotype were collected and assessed.Results: Of 91 patients with at least one pathogenic variant in the ABCA4 gene and fundal changes consistent with ABCA4 retinal dystrophy, 15 (16.5%) had peripheral pigmented retinal lesions in 20 eyes, and were bilateral in 6 patients. These flat, subretinal lesions were located in the mid- or far periphery, not involving the macula, and had well-defined borders. Most affected eyes had a solitary lesion (n = 18) with lesions more commonly present in the temporal half of the retina. Twenty-one unique genetic variants in ABCA4 were associated with these lesions. In 26 subjects (52 eyes) with RDS/PRPH-2-associated IRD, and in 30 age-matched controls (60 eyes), only one control eye had a pigmented lesion consistent with congenital hypertrophy of the retinal pigment epithelium and there were no peripheral pigmented lesions.Conclusions: Almost one-fifth of patients with ABCA4-associated retinopathy have peripheral pigmented retinal lesions. The presence of these lesions is associated with more severe disease with an earlier onset than in patients without the lesions, and is an aid to diagnosis.
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Affiliation(s)
- Haya H Al-Ani
- Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand.,Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Leo Sheck
- Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Andrea L Vincent
- Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand.,Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
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47
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Runhart EH, Khan M, Cornelis SS, Roosing S, Del Pozo-Valero M, Lamey TM, Liskova P, Roberts L, Stöhr H, Klaver CCW, Hoyng CB, Cremers FPM, Dhaenens CM. Association of Sex With Frequent and Mild ABCA4 Alleles in Stargardt Disease. JAMA Ophthalmol 2021; 138:1035-1042. [PMID: 32815999 DOI: 10.1001/jamaophthalmol.2020.2990] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Importance The mechanisms behind the phenotypic variability and reduced penetrance in autosomal recessive Stargardt disease (STGD1), often a blinding disease, are poorly understood. Identification of the unknown disease modifiers can improve patient and family counseling and provide valuable information for disease management. Objective To assess the association of incompletely penetrant ABCA4 alleles with sex in STGD1. Design, Setting, and Participants Genetic data for this cross-sectional study were obtained from 2 multicenter genetic studies of 1162 patients with clinically suspected STGD1. Unrelated patients with genetically confirmed STGD1 were selected. The data were collected from June 2016 to June 2019, and post hoc analysis was performed between July 2019 and January 2020. Main Outcomes and Measures Penetrance of reported mild ABCA4 variants was calculated by comparing the allele frequencies in the general population (obtained from the Genome Aggregation Database) with the genotyping data in the patient population (obtained from the ABCA4 Leiden Open Variation Database). The sex ratio among patients with and patients without an ABCA4 allele with incomplete penetrance was assessed. Results A total of 550 patients were included in the study, among which the mean (SD) age was 45.7 (18.0) years and most patients were women (311 [57%]). Five of the 5 mild ABCA4 alleles, including c.5603A>T and c.5882G>A, were calculated to have incomplete penetrance. The women to men ratio in the subgroup carrying c.5603A>T was 1.7 to 1; the proportion of women in this group was higher compared with the subgroup not carrying a mild allele (difference, 13%; 95% CI, 3%-23%; P = .02). The women to men ratio in the c.5882G>A subgroup was 2.1 to 1, and the women were overrepresented compared with the group carrying no mild allele (difference, 18%; 95% CI, 6%-30%; P = .005). Conclusions and Relevance This study found an imbalance in observed sex ratio among patients harboring a mild ABCA4 allele, which concerns approximately 25% of all patients with STGD1, suggesting that STGD1 should be considered a polygenic or multifactorial disease rather than a disease caused by ABCA4 gene mutations alone. The findings suggest that sex should be considered as a potential disease-modifying variable in both basic research and clinical trials on STGD1.
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Affiliation(s)
- Esmee H Runhart
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Mubeen Khan
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Stéphanie S Cornelis
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Susanne Roosing
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Marta Del Pozo-Valero
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain.,Center for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Tina M Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia.,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Petra Liskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Lisa Roberts
- University of Cape Town/MRC Genomic and Precision Medicine Research Unit, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Heidi Stöhr
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Caroline C W Klaver
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Ophthalmology, Erasmus Medical Center, Rotterdam, the Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, the Netherlands.,Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Frans P M Cremers
- Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Claire-Marie Dhaenens
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands.,University Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, Lille, France
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48
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Genetic characteristics and epidemiology of inherited retinal degeneration in Taiwan. NPJ Genom Med 2021; 6:16. [PMID: 33608557 PMCID: PMC7896090 DOI: 10.1038/s41525-021-00180-1] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 01/12/2021] [Indexed: 01/08/2023] Open
Abstract
Inherited retinal degenerations (IRDs) are a group of phenotypically and genotypically heterogeneous disorders with substantial socioeconomic impact. In this cohort study, we tried to address the genetic characteristics and epidemiology of IRDs in Taiwan. Totally, 312 families with IRDs were identified and recruited and genetic testing was performed via probe capture-based NGS targeting 212 IRD-related genes. Statistical analysis was based on the proband of each affected family. Disease-causing genotypes were identified in 178 families (57.1%). ABCA4 variants were the most common cause of disease in this cohort (27 families, 15.2%), whereas CYP4V2 variants were the most common cause for the single phenotype—Bietti’s crystalline dystrophy (12 families, 3.8%). Some variants such as ABCA4:c.1804C>T, CYP4V2:c.802-8_810delinsGC, and EYS:c6416G>A were population-specific disease-causing hotspots. Probands affected by ABCA4, RPGR, RP1L1, and CEP290 sought medical help earlier while patients affected by EYS and CYP4V2 visited our clinic at an older age. To evaluate the representativeness of our cohort in the genetic epidemiology of IRDs in Taiwan, our demographic data were compared with that of the total IRD population in Taiwan, obtained from the National Health Insurance Research Database. This is currently the largest-scale, comprehensive study investigating the genetic characteristics and epidemiology of IRD in Taiwan. These data could help patients and caregivers to adopt precision genomic medicine and novel gene therapies in near future.
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49
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Maggi J, Koller S, Bähr L, Feil S, Kivrak Pfiffner F, Hanson JVM, Maspoli A, Gerth-Kahlert C, Berger W. Long-Range PCR-Based NGS Applications to Diagnose Mendelian Retinal Diseases. Int J Mol Sci 2021; 22:ijms22041508. [PMID: 33546218 PMCID: PMC7913364 DOI: 10.3390/ijms22041508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/27/2022] Open
Abstract
The purpose of this study was to develop a flexible, cost-efficient, next-generation sequencing (NGS) protocol for genetic testing. Long-range polymerase chain reaction (PCR) amplicons of up to 20 kb in size were designed to amplify entire genomic regions for a panel (n = 35) of inherited retinal disease (IRD)-associated loci. Amplicons were pooled and sequenced by NGS. The analysis was applied to 227 probands diagnosed with IRD: (A) 108 previously molecularly diagnosed, (B) 94 without previous genetic testing, and (C) 25 undiagnosed after whole-exome sequencing (WES). The method was validated with 100% sensitivity on cohort A. Long-range PCR-based sequencing revealed likely causative variant(s) in 51% and 24% of proband from cohorts B and C, respectively. Breakpoints of 3 copy number variants (CNVs) could be characterized. Long-range PCR libraries spike-in extended coverage of WES. Read phasing confirmed compound heterozygosity in 5 probands. The proposed sequencing protocol provided deep coverage of the entire gene, including intronic and promoter regions. Our method can be used (i) as a first-tier assay to reduce genetic testing costs, (ii) to elucidate missing heritability cases, (iii) to characterize breakpoints of CNVs at nucleotide resolution, (iv) to extend WES data to non-coding regions by spiking-in long-range PCR libraries, and (v) to help with phasing of candidate variants.
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Affiliation(s)
- Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Luzy Bähr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Fatma Kivrak Pfiffner
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - James V. M. Hanson
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, 8091 Zurich, Switzerland; (J.V.M.H.); (C.G.-K.)
| | - Alessandro Maspoli
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital Zurich and University of Zurich, 8091 Zurich, Switzerland; (J.V.M.H.); (C.G.-K.)
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.); (L.B.); (S.F.); (F.K.P.); (A.M.)
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8057 Zurich, Switzerland
- Correspondence: ; Tel.: +41-44-556-33-50
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50
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Al-Khuzaei S, Shah M, Foster CR, Yu J, Broadgate S, Halford S, Downes SM. The role of multimodal imaging and vision function testing in ABCA4-related retinopathies and their relevance to future therapeutic interventions. Ther Adv Ophthalmol 2021; 13:25158414211056384. [PMID: 34988368 PMCID: PMC8721514 DOI: 10.1177/25158414211056384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 10/08/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of this review article is to describe the specific features of Stargardt disease and ABCA4 retinopathies (ABCA4R) using multimodal imaging and functional testing and to highlight their relevance to potential therapeutic interventions. Standardised measures of tissue loss, tissue function and rate of change over time using formal structured deep phenotyping in Stargardt disease and ABCA4R are key in diagnosis, and prognosis as well as when selecting cohorts for therapeutic intervention. In addition, a meticulous documentation of natural history will be invaluable in the future to compare treated with untreated retinas. Despite the familiarity with the term Stargardt disease, this eponymous classification alone is unhelpful when evaluating ABCA4R, as the ABCA4 gene is associated with a number of phenotypes, and a range of severity. Multimodal imaging, psychophysical and electrophysiologic measurements are necessary in diagnosing and characterising these differing retinopathies. A wide range of retinal dystrophy phenotypes are seen in association with ABCA4 mutations. In this article, these will be referred to as ABCA4R. These different phenotypes and the existence of phenocopies present a significant challenge to the clinician. Careful phenotypic characterisation coupled with the genotype enables the clinician to provide an accurate diagnosis, associated inheritance pattern and information regarding prognosis and management. This is particularly relevant now for recruiting to therapeutic trials, and in the future when therapies become available. The importance of accurate genotype-phenotype correlation studies cannot be overemphasised. This approach together with segregation studies can be vital in the identification of causal mutations when variants in more than one gene are being considered as possible. In this article, we give an overview of the current imaging, psychophysical and electrophysiological investigations, as well as current therapeutic research trials for retinopathies associated with the ABCA4 gene.
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Affiliation(s)
- Saoud Al-Khuzaei
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Mital Shah
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | | | | | | | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Susan M. Downes
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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